diff --git a/src/etc/mklldeps.py b/src/etc/mklldeps.py
index f184e07891b96..0003de117a835 100644
--- a/src/etc/mklldeps.py
+++ b/src/etc/mklldeps.py
@@ -67,7 +67,7 @@ def run(args):
         "target_os = \"" + os + "\"",
     ]
 
-    f.write("#[cfg(" + ', '.join(cfg) + ")]\n")
+    f.write("#[cfg(all(" + ', '.join(cfg) + "))]\n")
 
     version = run([llconfig, '--version']).strip()
 
diff --git a/src/liballoc/heap.rs b/src/liballoc/heap.rs
index 349ae15eb32a0..0d2872bcba06b 100644
--- a/src/liballoc/heap.rs
+++ b/src/liballoc/heap.rs
@@ -111,12 +111,12 @@ unsafe fn exchange_free(ptr: *mut u8, size: uint, align: uint) {
 // The minimum alignment guaranteed by the architecture. This value is used to
 // add fast paths for low alignment values. In practice, the alignment is a
 // constant at the call site and the branch will be optimized out.
-#[cfg(target_arch = "arm")]
-#[cfg(target_arch = "mips")]
-#[cfg(target_arch = "mipsel")]
+#[cfg(any(target_arch = "arm",
+          target_arch = "mips",
+          target_arch = "mipsel"))]
 static MIN_ALIGN: uint = 8;
-#[cfg(target_arch = "x86")]
-#[cfg(target_arch = "x86_64")]
+#[cfg(any(target_arch = "x86",
+          target_arch = "x86_64"))]
 static MIN_ALIGN: uint = 16;
 
 #[cfg(jemalloc)]
@@ -146,7 +146,7 @@ mod imp {
     }
 
     // -lpthread needs to occur after -ljemalloc, the earlier argument isn't enough
-    #[cfg(not(windows), not(target_os = "android"))]
+    #[cfg(all(not(windows), not(target_os = "android")))]
     #[link(name = "pthread")]
     extern {}
 
@@ -206,7 +206,7 @@ mod imp {
     }
 }
 
-#[cfg(not(jemalloc), unix)]
+#[cfg(all(not(jemalloc), unix))]
 mod imp {
     use core::cmp;
     use core::ptr;
@@ -268,7 +268,7 @@ mod imp {
     pub fn stats_print() {}
 }
 
-#[cfg(not(jemalloc), windows)]
+#[cfg(all(not(jemalloc), windows))]
 mod imp {
     use libc::{c_void, size_t};
     use libc;
diff --git a/src/libgreen/context.rs b/src/libgreen/context.rs
index 296615e15ffa0..a665d41aadf96 100644
--- a/src/libgreen/context.rs
+++ b/src/libgreen/context.rs
@@ -188,27 +188,27 @@ fn initialize_call_frame(regs: &mut Registers, fptr: InitFn, arg: uint,
 
 // windows requires saving more registers (both general and XMM), so the windows
 // register context must be larger.
-#[cfg(windows, target_arch = "x86_64")]
+#[cfg(all(windows, target_arch = "x86_64"))]
 #[repr(C)]
 struct Registers {
     gpr:[libc::uintptr_t, ..14],
     _xmm:[simd::u32x4, ..10]
 }
-#[cfg(not(windows), target_arch = "x86_64")]
+#[cfg(all(not(windows), target_arch = "x86_64"))]
 #[repr(C)]
 struct Registers {
     gpr:[libc::uintptr_t, ..10],
     _xmm:[simd::u32x4, ..6]
 }
 
-#[cfg(windows, target_arch = "x86_64")]
+#[cfg(all(windows, target_arch = "x86_64"))]
 fn new_regs() -> Box<Registers> {
     box() Registers {
         gpr:[0,..14],
         _xmm:[simd::u32x4(0,0,0,0),..10]
     }
 }
-#[cfg(not(windows), target_arch = "x86_64")]
+#[cfg(all(not(windows), target_arch = "x86_64"))]
 fn new_regs() -> Box<Registers> {
     box() Registers {
         gpr:[0,..10],
@@ -288,16 +288,13 @@ fn initialize_call_frame(regs: &mut Registers, fptr: InitFn, arg: uint,
     regs[14] = rust_bootstrap_green_task as libc::uintptr_t;   // #56 pc, r14 --> lr
 }
 
-#[cfg(target_arch = "mips")]
-#[cfg(target_arch = "mipsel")]
+#[cfg(any(target_arch = "mips", target_arch = "mipsel"))]
 type Registers = [libc::uintptr_t, ..32];
 
-#[cfg(target_arch = "mips")]
-#[cfg(target_arch = "mipsel")]
+#[cfg(any(target_arch = "mips", target_arch = "mipsel"))]
 fn new_regs() -> Box<Registers> { box {[0, .. 32]} }
 
-#[cfg(target_arch = "mips")]
-#[cfg(target_arch = "mipsel")]
+#[cfg(any(target_arch = "mips", target_arch = "mipsel"))]
 fn initialize_call_frame(regs: &mut Registers, fptr: InitFn, arg: uint,
                          procedure: raw::Procedure, sp: *mut uint) {
     let sp = align_down(sp);
diff --git a/src/libgreen/stack.rs b/src/libgreen/stack.rs
index 4673e7b3ba209..23b41f6c6e75b 100644
--- a/src/libgreen/stack.rs
+++ b/src/libgreen/stack.rs
@@ -28,11 +28,10 @@ pub struct Stack {
 //
 // DragonFly BSD also seems to suffer from the same problem. When MAP_STACK is
 // used, it returns the same `ptr` multiple times.
-#[cfg(not(windows), not(target_os = "freebsd"), not(target_os = "dragonfly"))]
+#[cfg(not(any(windows, target_os = "freebsd", target_os = "dragonfly")))]
 static STACK_FLAGS: libc::c_int = libc::MAP_STACK | libc::MAP_PRIVATE |
                                   libc::MAP_ANON;
-#[cfg(target_os = "freebsd")]
-#[cfg(target_os = "dragonfly")]
+#[cfg(any(target_os = "freebsd", target_os = "dragonfly"))]
 static STACK_FLAGS: libc::c_int = libc::MAP_PRIVATE | libc::MAP_ANON;
 #[cfg(windows)]
 static STACK_FLAGS: libc::c_int = 0;
diff --git a/src/liblibc/lib.rs b/src/liblibc/lib.rs
index eabc02e3e26eb..affa452eb49de 100644
--- a/src/liblibc/lib.rs
+++ b/src/liblibc/lib.rs
@@ -278,32 +278,31 @@ pub use funcs::bsd43::{shutdown};
 #[cfg(windows)] pub use funcs::extra::msvcrt::{get_osfhandle, open_osfhandle};
 #[cfg(windows)] pub use funcs::extra::winsock::{ioctlsocket};
 
-#[cfg(target_os = "linux")] #[cfg(target_os = "android")]
-#[cfg(target_os = "freebsd")] #[cfg(target_os = "dragonfly")]
+#[cfg(any(target_os = "linux",
+          target_os = "android",
+          target_os = "freebsd",
+          target_os = "dragonfly"))]
 pub use consts::os::posix01::{CLOCK_REALTIME, CLOCK_MONOTONIC};
 
-#[cfg(target_os = "linux")] #[cfg(target_os = "android")]
+#[cfg(any(target_os = "linux", target_os = "android"))]
 pub use funcs::posix01::unistd::{fdatasync};
-#[cfg(target_os = "linux")] #[cfg(target_os = "android")]
+#[cfg(any(target_os = "linux", target_os = "android"))]
 pub use types::os::arch::extra::{sockaddr_ll};
-#[cfg(target_os = "linux")] #[cfg(target_os = "android")]
+#[cfg(any(target_os = "linux", target_os = "android"))]
 pub use consts::os::extra::{AF_PACKET};
 
-#[cfg(unix, not(target_os = "freebsd"))]
+#[cfg(all(unix, not(target_os = "freebsd")))]
 pub use consts::os::extra::{MAP_STACK};
 
-#[cfg(target_os = "freebsd")]
-#[cfg(target_os = "dragonfly")]
+#[cfg(any(target_os = "freebsd", target_os = "dragonfly"))]
 pub use consts::os::bsd44::{TCP_KEEPIDLE};
 
-#[cfg(target_os = "macos")]
-#[cfg(target_os = "ios")]
+#[cfg(any(target_os = "macos", target_os = "ios"))]
 pub use consts::os::bsd44::{TCP_KEEPALIVE};
-#[cfg(target_os = "macos")]
-#[cfg(target_os = "ios")]
+#[cfg(any(target_os = "macos", target_os = "ios"))]
 pub use consts::os::extra::{F_FULLFSYNC};
-#[cfg(target_os = "macos")]
-#[cfg(target_os = "ios")]
+
+#[cfg(any(target_os = "macos", target_os = "ios"))]
 pub use types::os::arch::extra::{mach_timebase_info};
 
 
@@ -372,8 +371,7 @@ pub mod types {
 
     // Standard types that are scalar but vary by OS and arch.
 
-    #[cfg(target_os = "linux")]
-    #[cfg(target_os = "android")]
+    #[cfg(any(target_os = "linux", target_os = "android"))]
     pub mod os {
         pub mod common {
             pub mod posix01 {
@@ -506,10 +504,10 @@ pub mod types {
             }
         }
 
-        #[cfg(target_arch = "x86")]
-        #[cfg(target_arch = "arm")]
-        #[cfg(target_arch = "mips")]
-        #[cfg(target_arch = "mipsel")]
+        #[cfg(any(target_arch = "x86",
+                  target_arch = "arm",
+                  target_arch = "mips",
+                  target_arch = "mipsel"))]
         pub mod arch {
             pub mod c95 {
                 pub type c_char = i8;
@@ -536,9 +534,9 @@ pub mod types {
                 pub type intptr_t = i32;
                 pub type uintptr_t = u32;
             }
-            #[cfg(target_arch = "x86")]
-            #[cfg(target_arch = "mips")]
-            #[cfg(target_arch = "mipsel")]
+            #[cfg(any(target_arch = "x86",
+                      target_arch = "mips",
+                      target_arch = "mipsel"))]
             pub mod posix88 {
                 pub type off_t = i32;
                 pub type dev_t = u64;
@@ -652,8 +650,7 @@ pub mod types {
                     pub __size: [u32, ..9]
                 }
             }
-            #[cfg(target_arch = "mips")]
-            #[cfg(target_arch = "mipsel")]
+            #[cfg(any(target_arch = "mips", target_arch = "mipsel"))]
             pub mod posix01 {
                 use types::os::arch::c95::{c_long, c_ulong, time_t};
                 use types::os::arch::posix88::{gid_t, ino_t};
@@ -1660,8 +1657,7 @@ pub mod types {
         }
     }
 
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
+    #[cfg(any(target_os = "macos", target_os = "ios"))]
     pub mod os {
         pub mod common {
             pub mod posix01 {
@@ -1793,8 +1789,7 @@ pub mod types {
             }
         }
 
-        #[cfg(target_arch = "arm")]
-        #[cfg(target_arch = "x86")]
+        #[cfg(any(target_arch = "arm", target_arch = "x86"))]
         pub mod arch {
             pub mod c95 {
                 pub type c_char = i8;
@@ -2383,8 +2378,7 @@ pub mod consts {
     }
 
 
-    #[cfg(target_os = "linux")]
-    #[cfg(target_os = "android")]
+    #[cfg(any(target_os = "linux", target_os = "android"))]
     pub mod os {
         pub mod c95 {
             use types::os::arch::c95::{c_int, c_uint};
@@ -2407,9 +2401,9 @@ pub mod consts {
         }
         pub mod c99 {
         }
-        #[cfg(target_arch = "x86")]
-        #[cfg(target_arch = "x86_64")]
-        #[cfg(target_arch = "arm")]
+        #[cfg(any(target_arch = "x86",
+                  target_arch = "x86_64",
+                  target_arch = "arm"))]
         pub mod posix88 {
             use types::os::arch::c95::c_int;
             use types::common::c95::c_void;
@@ -2621,8 +2615,7 @@ pub mod consts {
             pub static EHWPOISON: c_int = 133;
         }
 
-        #[cfg(target_arch = "mips")]
-        #[cfg(target_arch = "mipsel")]
+        #[cfg(any(target_arch = "mips", target_arch = "mipsel"))]
         pub mod posix88 {
             use types::os::arch::c95::c_int;
             use types::common::c95::c_void;
@@ -2898,13 +2891,14 @@ pub mod consts {
             #[cfg(target_os = "android")]
             pub static PTHREAD_STACK_MIN: size_t = 8192;
 
-            #[cfg(target_arch = "arm", target_os = "linux")]
-            #[cfg(target_arch = "x86", target_os = "linux")]
-            #[cfg(target_arch = "x86_64", target_os = "linux")]
+            #[cfg(all(target_os = "linux",
+                      any(target_arch = "arm",
+                          target_arch = "x86",
+                          target_arch = "x86_64")))]
             pub static PTHREAD_STACK_MIN: size_t = 16384;
 
-            #[cfg(target_arch = "mips", target_os = "linux")]
-            #[cfg(target_arch = "mipsel", target_os = "linux")]
+            #[cfg(all(target_os = "linux",
+                      any(target_arch = "mips", target_arch = "mipsel")))]
             pub static PTHREAD_STACK_MIN: size_t = 131072;
 
             pub static CLOCK_REALTIME: c_int = 0;
@@ -2912,9 +2906,9 @@ pub mod consts {
         }
         pub mod posix08 {
         }
-        #[cfg(target_arch = "arm")]
-        #[cfg(target_arch = "x86")]
-        #[cfg(target_arch = "x86_64")]
+        #[cfg(any(target_arch = "arm",
+                  target_arch = "x86",
+                  target_arch = "x86_64"))]
         pub mod bsd44 {
             use types::os::arch::c95::c_int;
 
@@ -2961,8 +2955,7 @@ pub mod consts {
             pub static SHUT_WR: c_int = 1;
             pub static SHUT_RDWR: c_int = 2;
         }
-        #[cfg(target_arch = "mips")]
-        #[cfg(target_arch = "mipsel")]
+        #[cfg(any(target_arch = "mips", target_arch = "mipsel"))]
         pub mod bsd44 {
             use types::os::arch::c95::c_int;
 
@@ -3007,9 +3000,9 @@ pub mod consts {
             pub static SHUT_WR: c_int = 1;
             pub static SHUT_RDWR: c_int = 2;
         }
-        #[cfg(target_arch = "x86")]
-        #[cfg(target_arch = "x86_64")]
-        #[cfg(target_arch = "arm")]
+        #[cfg(any(target_arch = "x86",
+                  target_arch = "x86_64",
+                  target_arch = "arm"))]
         pub mod extra {
             use types::os::arch::c95::c_int;
 
@@ -3036,8 +3029,7 @@ pub mod consts {
             pub static MAP_NONBLOCK : c_int = 0x010000;
             pub static MAP_STACK : c_int = 0x020000;
         }
-        #[cfg(target_arch = "mips")]
-        #[cfg(target_arch = "mipsel")]
+        #[cfg(any(target_arch = "mips", target_arch = "mipsel"))]
         pub mod extra {
             use types::os::arch::c95::c_int;
 
@@ -3160,8 +3152,7 @@ pub mod consts {
         }
     }
 
-    #[cfg(target_os = "freebsd")]
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "freebsd", target_os = "dragonfly"))]
     pub mod os {
         pub mod c95 {
             use types::os::arch::c95::{c_int, c_uint};
@@ -3421,10 +3412,11 @@ pub mod consts {
             #[cfg(target_arch = "arm")]
             pub static PTHREAD_STACK_MIN: size_t = 4096;
 
-            #[cfg(target_os = "freebsd", target_arch = "mips")]
-            #[cfg(target_os = "freebsd", target_arch = "mipsel")]
-            #[cfg(target_os = "freebsd", target_arch = "x86")]
-            #[cfg(target_os = "freebsd", target_arch = "x86_64")]
+            #[cfg(all(target_os = "freebsd",
+                      any(target_arch = "mips",
+                          target_arch = "mipsel",
+                          target_arch = "x86",
+                          target_arch = "x86_64")))]
             pub static PTHREAD_STACK_MIN: size_t = 2048;
 
             #[cfg(target_os = "dragonfly")]
@@ -3569,8 +3561,7 @@ pub mod consts {
         }
     }
 
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
+    #[cfg(any(target_os = "macos", target_os = "ios"))]
     pub mod os {
         pub mod c95 {
             use types::os::arch::c95::{c_int, c_uint};
@@ -4261,13 +4252,12 @@ pub mod funcs {
         }
     }
 
-
-    #[cfg(target_os = "linux")]
-    #[cfg(target_os = "android")]
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
-    #[cfg(target_os = "freebsd")]
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "linux",
+              target_os = "android",
+              target_os = "macos",
+              target_os = "ios",
+              target_os = "freebsd",
+              target_os = "dragonfly"))]
     pub mod posix88 {
         pub mod stat_ {
             use types::os::arch::c95::{c_char, c_int};
@@ -4278,11 +4268,11 @@ pub mod funcs {
                 pub fn chmod(path: *const c_char, mode: mode_t) -> c_int;
                 pub fn fchmod(fd: c_int, mode: mode_t) -> c_int;
 
-                #[cfg(target_os = "linux")]
-                #[cfg(target_os = "freebsd")]
-                #[cfg(target_os = "dragonfly")]
-                #[cfg(target_os = "android")]
-                #[cfg(target_os = "ios")]
+                #[cfg(any(target_os = "linux",
+                          target_os = "freebsd",
+                          target_os = "dragonfly",
+                          target_os = "android",
+                          target_os = "ios"))]
                 pub fn fstat(fildes: c_int, buf: *mut stat) -> c_int;
 
                 #[cfg(target_os = "macos")]
@@ -4292,11 +4282,11 @@ pub mod funcs {
                 pub fn mkdir(path: *const c_char, mode: mode_t) -> c_int;
                 pub fn mkfifo(path: *const c_char, mode: mode_t) -> c_int;
 
-                #[cfg(target_os = "linux")]
-                #[cfg(target_os = "freebsd")]
-                #[cfg(target_os = "dragonfly")]
-                #[cfg(target_os = "android")]
-                #[cfg(target_os = "ios")]
+                #[cfg(any(target_os = "linux",
+                          target_os = "freebsd",
+                          target_os = "dragonfly",
+                          target_os = "android",
+                          target_os = "ios"))]
                 pub fn stat(path: *const c_char, buf: *mut stat) -> c_int;
 
                 #[cfg(target_os = "macos")]
@@ -4481,23 +4471,23 @@ pub mod funcs {
 
     }
 
-    #[cfg(target_os = "linux")]
-    #[cfg(target_os = "android")]
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
-    #[cfg(target_os = "freebsd")]
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "linux",
+              target_os = "android",
+              target_os = "macos",
+              target_os = "ios",
+              target_os = "freebsd",
+              target_os = "dragonfly"))]
     pub mod posix01 {
         pub mod stat_ {
             use types::os::arch::c95::{c_char, c_int};
             use types::os::arch::posix01::stat;
 
             extern {
-                #[cfg(target_os = "linux")]
-                #[cfg(target_os = "freebsd")]
-                #[cfg(target_os = "dragonfly")]
-                #[cfg(target_os = "android")]
-                #[cfg(target_os = "ios")]
+                #[cfg(any(target_os = "linux",
+                          target_os = "freebsd",
+                          target_os = "dragonfly",
+                          target_os = "android",
+                          target_os = "ios"))]
                 pub fn lstat(path: *const c_char, buf: *mut stat) -> c_int;
 
                 #[cfg(target_os = "macos")]
@@ -4518,8 +4508,7 @@ pub mod funcs {
 
                 pub fn fsync(fd: c_int) -> c_int;
 
-                #[cfg(target_os = "linux")]
-                #[cfg(target_os = "android")]
+                #[cfg(any(target_os = "linux", target_os = "android"))]
                 pub fn fdatasync(fd: c_int) -> c_int;
 
                 pub fn setenv(name: *const c_char, val: *const c_char,
@@ -4598,13 +4587,13 @@ pub mod funcs {
     }
 
 
-    #[cfg(target_os = "windows")]
-    #[cfg(target_os = "linux")]
-    #[cfg(target_os = "android")]
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
-    #[cfg(target_os = "freebsd")]
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "windows",
+              target_os = "linux",
+              target_os = "android",
+              target_os = "macos",
+              target_os = "ios",
+              target_os = "freebsd",
+              target_os = "dragonfly"))]
     pub mod posix08 {
         pub mod unistd {
         }
@@ -4687,10 +4676,10 @@ pub mod funcs {
         }
     }
 
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
-    #[cfg(target_os = "freebsd")]
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "macos",
+              target_os = "ios",
+              target_os = "freebsd",
+              target_os = "dragonfly"))]
     pub mod bsd44 {
         use types::common::c95::{c_void};
         use types::os::arch::c95::{c_char, c_uchar, c_int, c_uint, c_ulong, size_t};
@@ -4723,8 +4712,7 @@ pub mod funcs {
     }
 
 
-    #[cfg(target_os = "linux")]
-    #[cfg(target_os = "android")]
+    #[cfg(any(target_os = "linux", target_os = "android"))]
     pub mod bsd44 {
         use types::common::c95::{c_void};
         use types::os::arch::c95::{c_uchar, c_int, size_t};
@@ -4744,8 +4732,7 @@ pub mod funcs {
     pub mod bsd44 {
     }
 
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
+    #[cfg(any(target_os = "macos", target_os = "ios"))]
     pub mod extra {
         use types::os::arch::c95::{c_char, c_int};
 
@@ -4755,13 +4742,11 @@ pub mod funcs {
         }
     }
 
-    #[cfg(target_os = "freebsd")]
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "freebsd", target_os = "dragonfly"))]
     pub mod extra {
     }
 
-    #[cfg(target_os = "linux")]
-    #[cfg(target_os = "android")]
+    #[cfg(any(target_os = "linux", target_os = "android"))]
     pub mod extra {
     }
 
diff --git a/src/libnative/io/c_unix.rs b/src/libnative/io/c_unix.rs
index fa7da1de914b4..2601d493443a1 100644
--- a/src/libnative/io/c_unix.rs
+++ b/src/libnative/io/c_unix.rs
@@ -19,41 +19,42 @@ pub use self::signal::{SA_NODEFER, SA_NOCLDWAIT, SA_SIGINFO, SIGCHLD};
 
 use libc;
 
-#[cfg(target_os = "macos")]
-#[cfg(target_os = "ios")]
-#[cfg(target_os = "freebsd")]
-#[cfg(target_os = "dragonfly")]
+#[cfg(any(target_os = "macos",
+          target_os = "ios",
+          target_os = "freebsd",
+          target_os = "dragonfly"))]
 pub static FIONBIO: libc::c_ulong = 0x8004667e;
-#[cfg(target_os = "linux", target_arch = "x86")]
-#[cfg(target_os = "linux", target_arch = "x86_64")]
-#[cfg(target_os = "linux", target_arch = "arm")]
-#[cfg(target_os = "android")]
+#[cfg(any(all(target_os = "linux",
+              any(target_arch = "x86",
+                  target_arch = "x86_64",
+                  target_arch = "arm")),
+          target_os = "android"))]
 pub static FIONBIO: libc::c_ulong = 0x5421;
-#[cfg(target_os = "linux", target_arch = "mips")]
-#[cfg(target_os = "linux", target_arch = "mipsel")]
+#[cfg(all(target_os = "linux",
+          any(target_arch = "mips", target_arch = "mipsel")))]
 pub static FIONBIO: libc::c_ulong = 0x667e;
 
-#[cfg(target_os = "macos")]
-#[cfg(target_os = "ios")]
-#[cfg(target_os = "freebsd")]
-#[cfg(target_os = "dragonfly")]
+#[cfg(any(target_os = "macos",
+          target_os = "ios",
+          target_os = "freebsd",
+          target_os = "dragonfly"))]
 pub static FIOCLEX: libc::c_ulong = 0x20006601;
-#[cfg(target_os = "linux", target_arch = "x86")]
-#[cfg(target_os = "linux", target_arch = "x86_64")]
-#[cfg(target_os = "linux", target_arch = "arm")]
-#[cfg(target_os = "android")]
+#[cfg(any(all(target_os = "linux",
+              any(target_arch = "x86",
+                  target_arch = "x86_64",
+                  target_arch = "arm")),
+          target_os = "android"))]
 pub static FIOCLEX: libc::c_ulong = 0x5451;
-#[cfg(target_os = "linux", target_arch = "mips")]
-#[cfg(target_os = "linux", target_arch = "mipsel")]
+#[cfg(all(target_os = "linux",
+          any(target_arch = "mips", target_arch = "mipsel")))]
 pub static FIOCLEX: libc::c_ulong = 0x6601;
 
-#[cfg(target_os = "macos")]
-#[cfg(target_os = "ios")]
-#[cfg(target_os = "freebsd")]
-#[cfg(target_os = "dragonfly")]
+#[cfg(any(target_os = "macos",
+          target_os = "ios",
+          target_os = "freebsd",
+          target_os = "dragonfly"))]
 pub static MSG_DONTWAIT: libc::c_int = 0x80;
-#[cfg(target_os = "linux")]
-#[cfg(target_os = "android")]
+#[cfg(any(target_os = "linux", target_os = "android"))]
 pub static MSG_DONTWAIT: libc::c_int = 0x40;
 
 pub static WNOHANG: libc::c_int = 1;
@@ -86,8 +87,7 @@ extern {
     pub fn sigemptyset(set: *mut sigset_t) -> libc::c_int;
 }
 
-#[cfg(target_os = "macos")]
-#[cfg(target_os = "ios")]
+#[cfg(any(target_os = "macos", target_os = "ios"))]
 mod select {
     pub static FD_SETSIZE: uint = 1024;
 
@@ -101,10 +101,10 @@ mod select {
     }
 }
 
-#[cfg(target_os = "android")]
-#[cfg(target_os = "freebsd")]
-#[cfg(target_os = "dragonfly")]
-#[cfg(target_os = "linux")]
+#[cfg(any(target_os = "android",
+          target_os = "freebsd",
+          target_os = "dragonfly",
+          target_os = "linux"))]
 mod select {
     use std::uint;
     use libc;
@@ -123,10 +123,11 @@ mod select {
     }
 }
 
-#[cfg(target_os = "linux", target_arch = "x86")]
-#[cfg(target_os = "linux", target_arch = "x86_64")]
-#[cfg(target_os = "linux", target_arch = "arm")]
-#[cfg(target_os = "android")]
+#[cfg(any(all(target_os = "linux",
+              any(target_arch = "x86",
+                  target_arch = "x86_64",
+                  target_arch = "arm")),
+          target_os = "android"))]
 mod signal {
     use libc;
 
@@ -173,8 +174,8 @@ mod signal {
     }
 }
 
-#[cfg(target_os = "linux", target_arch = "mips")]
-#[cfg(target_os = "linux", target_arch = "mipsel")]
+#[cfg(all(target_os = "linux",
+          any(target_arch = "mips", target_arch = "mipsel")))]
 mod signal {
     use libc;
 
@@ -215,10 +216,10 @@ mod signal {
     }
 }
 
-#[cfg(target_os = "macos")]
-#[cfg(target_os = "ios")]
-#[cfg(target_os = "freebsd")]
-#[cfg(target_os = "dragonfly")]
+#[cfg(any(target_os = "macos",
+          target_os = "ios",
+          target_os = "freebsd",
+          target_os = "dragonfly"))]
 mod signal {
     use libc;
 
diff --git a/src/libnative/io/file_unix.rs b/src/libnative/io/file_unix.rs
index 1688b009ad7fb..67aad1904b96f 100644
--- a/src/libnative/io/file_unix.rs
+++ b/src/libnative/io/file_unix.rs
@@ -130,8 +130,7 @@ impl rtio::RtioFileStream for FileDesc {
     fn datasync(&mut self) -> IoResult<()> {
         return super::mkerr_libc(os_datasync(self.fd()));
 
-        #[cfg(target_os = "macos")]
-        #[cfg(target_os = "ios")]
+        #[cfg(any(target_os = "macos", target_os = "ios"))]
         fn os_datasync(fd: c_int) -> c_int {
             unsafe { libc::fcntl(fd, libc::F_FULLFSYNC) }
         }
@@ -139,7 +138,7 @@ impl rtio::RtioFileStream for FileDesc {
         fn os_datasync(fd: c_int) -> c_int {
             retry(|| unsafe { libc::fdatasync(fd) })
         }
-        #[cfg(not(target_os = "macos"), not(target_os = "ios"), not(target_os = "linux"))]
+        #[cfg(not(any(target_os = "macos", target_os = "ios", target_os = "linux")))]
         fn os_datasync(fd: c_int) -> c_int {
             retry(|| unsafe { libc::fsync(fd) })
         }
@@ -445,14 +444,14 @@ fn mkstat(stat: &libc::stat) -> rtio::FileStat {
     // FileStat times are in milliseconds
     fn mktime(secs: u64, nsecs: u64) -> u64 { secs * 1000 + nsecs / 1000000 }
 
-    #[cfg(not(target_os = "linux"), not(target_os = "android"))]
+    #[cfg(not(any(target_os = "linux", target_os = "android")))]
     fn flags(stat: &libc::stat) -> u64 { stat.st_flags as u64 }
-    #[cfg(target_os = "linux")] #[cfg(target_os = "android")]
+    #[cfg(any(target_os = "linux", target_os = "android"))]
     fn flags(_stat: &libc::stat) -> u64 { 0 }
 
-    #[cfg(not(target_os = "linux"), not(target_os = "android"))]
+    #[cfg(not(any(target_os = "linux", target_os = "android")))]
     fn gen(stat: &libc::stat) -> u64 { stat.st_gen as u64 }
-    #[cfg(target_os = "linux")] #[cfg(target_os = "android")]
+    #[cfg(any(target_os = "linux", target_os = "android"))]
     fn gen(_stat: &libc::stat) -> u64 { 0 }
 
     rtio::FileStat {
diff --git a/src/libnative/io/mod.rs b/src/libnative/io/mod.rs
index 86f72bf65ddd3..954f7bbc59adc 100644
--- a/src/libnative/io/mod.rs
+++ b/src/libnative/io/mod.rs
@@ -48,12 +48,12 @@ pub mod file;
 #[path = "file_windows.rs"]
 pub mod file;
 
-#[cfg(target_os = "macos")]
-#[cfg(target_os = "ios")]
-#[cfg(target_os = "freebsd")]
-#[cfg(target_os = "dragonfly")]
-#[cfg(target_os = "android")]
-#[cfg(target_os = "linux")]
+#[cfg(any(target_os = "macos",
+          target_os = "ios",
+          target_os = "freebsd",
+          target_os = "dragonfly",
+          target_os = "android",
+          target_os = "linux"))]
 #[path = "timer_unix.rs"]
 pub mod timer;
 
diff --git a/src/libnative/io/net.rs b/src/libnative/io/net.rs
index 335a52b0bbed6..419748b75c324 100644
--- a/src/libnative/io/net.rs
+++ b/src/libnative/io/net.rs
@@ -282,20 +282,20 @@ impl TcpStream {
         }
     }
 
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
+    #[cfg(any(target_os = "macos", target_os = "ios"))]
     fn set_tcp_keepalive(&mut self, seconds: uint) -> IoResult<()> {
         setsockopt(self.fd(), libc::IPPROTO_TCP, libc::TCP_KEEPALIVE,
                    seconds as libc::c_int)
     }
-    #[cfg(target_os = "freebsd")]
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "freebsd", target_os = "dragonfly"))]
     fn set_tcp_keepalive(&mut self, seconds: uint) -> IoResult<()> {
         setsockopt(self.fd(), libc::IPPROTO_TCP, libc::TCP_KEEPIDLE,
                    seconds as libc::c_int)
     }
-    #[cfg(not(target_os = "macos"), not(target_os = "ios"), not(target_os = "freebsd"),
-      not(target_os = "dragonfly"))]
+    #[cfg(not(any(target_os = "macos",
+                  target_os = "ios",
+                  target_os = "freebsd",
+                  target_os = "dragonfly")))]
     fn set_tcp_keepalive(&mut self, _seconds: uint) -> IoResult<()> {
         Ok(())
     }
diff --git a/src/libnative/io/process.rs b/src/libnative/io/process.rs
index cb392e1675feb..3a6ae42f9468d 100644
--- a/src/libnative/io/process.rs
+++ b/src/libnative/io/process.rs
@@ -840,18 +840,17 @@ fn free_handle(_handle: *mut ()) {
 #[cfg(unix)]
 fn translate_status(status: c_int) -> rtio::ProcessExit {
     #![allow(non_snake_case)]
-    #[cfg(target_os = "linux")]
-    #[cfg(target_os = "android")]
+    #[cfg(any(target_os = "linux", target_os = "android"))]
     mod imp {
         pub fn WIFEXITED(status: i32) -> bool { (status & 0xff) == 0 }
         pub fn WEXITSTATUS(status: i32) -> i32 { (status >> 8) & 0xff }
         pub fn WTERMSIG(status: i32) -> i32 { status & 0x7f }
     }
 
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
-    #[cfg(target_os = "freebsd")]
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "macos",
+              target_os = "ios",
+              target_os = "freebsd",
+              target_os = "dragonfly"))]
     mod imp {
         pub fn WIFEXITED(status: i32) -> bool { (status & 0x7f) == 0 }
         pub fn WEXITSTATUS(status: i32) -> i32 { status >> 8 }
diff --git a/src/libnative/lib.rs b/src/libnative/lib.rs
index 06f89d38ca0a1..267ff3d2a8174 100644
--- a/src/libnative/lib.rs
+++ b/src/libnative/lib.rs
@@ -77,10 +77,9 @@ pub use task::NativeTaskBuilder;
 pub mod io;
 pub mod task;
 
-#[cfg(windows)]
-#[cfg(android)]
+#[cfg(any(windows, android))]
 static OS_DEFAULT_STACK_ESTIMATE: uint = 1 << 20;
-#[cfg(unix, not(android))]
+#[cfg(all(unix, not(android)))]
 static OS_DEFAULT_STACK_ESTIMATE: uint = 2 * (1 << 20);
 
 #[lang = "start"]
diff --git a/src/librustc/middle/trans/asm.rs b/src/librustc/middle/trans/asm.rs
index c51e242026241..d898931cb330b 100644
--- a/src/librustc/middle/trans/asm.rs
+++ b/src/librustc/middle/trans/asm.rs
@@ -162,15 +162,14 @@ pub fn trans_inline_asm<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, ia: &ast::InlineAsm)
 // Default per-arch clobbers
 // Basically what clang does
 
-#[cfg(target_arch = "arm")]
-#[cfg(target_arch = "mips")]
-#[cfg(target_arch = "mipsel")]
+#[cfg(any(target_arch = "arm",
+          target_arch = "mips",
+          target_arch = "mipsel"))]
 fn get_clobbers() -> String {
     "".to_string()
 }
 
-#[cfg(target_arch = "x86")]
-#[cfg(target_arch = "x86_64")]
+#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 fn get_clobbers() -> String {
     "~{dirflag},~{fpsr},~{flags}".to_string()
 }
diff --git a/src/librustc_back/fs.rs b/src/librustc_back/fs.rs
index c051b8e60cd80..756516d17a2ea 100644
--- a/src/librustc_back/fs.rs
+++ b/src/librustc_back/fs.rs
@@ -51,7 +51,7 @@ pub fn realpath(original: &Path) -> io::IoResult<Path> {
     return Ok(result);
 }
 
-#[cfg(not(windows), test)]
+#[cfg(all(not(windows), test))]
 mod test {
     use std::io;
     use std::io::fs::{File, symlink, mkdir, mkdir_recursive};
diff --git a/src/librustc_back/rpath.rs b/src/librustc_back/rpath.rs
index e0946366abc81..abb594d6e47a8 100644
--- a/src/librustc_back/rpath.rs
+++ b/src/librustc_back/rpath.rs
@@ -147,7 +147,7 @@ fn minimize_rpaths(rpaths: &[String]) -> Vec<String> {
     minimized
 }
 
-#[cfg(unix, test)]
+#[cfg(all(unix, test))]
 mod test {
     use super::{RPathConfig};
     use super::{minimize_rpaths, rpaths_to_flags, get_rpath_relative_to_output};
diff --git a/src/librustdoc/flock.rs b/src/librustdoc/flock.rs
index 8b72bd9e10283..d1cc37497dc44 100644
--- a/src/librustdoc/flock.rs
+++ b/src/librustdoc/flock.rs
@@ -84,8 +84,7 @@ mod imp {
         pub static F_SETLKW: libc::c_int = 9;
     }
 
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
+    #[cfg(any(target_os = "macos", target_os = "ios"))]
     mod os {
         use libc;
 
diff --git a/src/librustdoc/plugins.rs b/src/librustdoc/plugins.rs
index fe217a6d123aa..2b5595131d0a7 100644
--- a/src/librustdoc/plugins.rs
+++ b/src/librustdoc/plugins.rs
@@ -85,7 +85,7 @@ fn libname(mut n: String) -> String {
     n
 }
 
-#[cfg(not(target_os="windows"), not(target_os="macos"))]
+#[cfg(all(not(target_os="windows"), not(target_os="macos")))]
 fn libname(n: String) -> String {
     let mut i = String::from_str("lib");
     i.push_str(n.as_slice());
diff --git a/src/librustrt/args.rs b/src/librustrt/args.rs
index c0a17a7201473..bd63886baeeda 100644
--- a/src/librustrt/args.rs
+++ b/src/librustrt/args.rs
@@ -39,10 +39,10 @@ pub fn put(args: Vec<Vec<u8>>) { imp::put(args) }
 /// Make a clone of the global arguments.
 pub fn clone() -> Option<Vec<Vec<u8>>> { imp::clone() }
 
-#[cfg(target_os = "linux")]
-#[cfg(target_os = "android")]
-#[cfg(target_os = "freebsd")]
-#[cfg(target_os = "dragonfly")]
+#[cfg(any(target_os = "linux",
+          target_os = "android",
+          target_os = "freebsd",
+          target_os = "dragonfly"))]
 mod imp {
     use core::prelude::*;
 
@@ -146,9 +146,9 @@ mod imp {
     }
 }
 
-#[cfg(target_os = "macos")]
-#[cfg(target_os = "ios")]
-#[cfg(target_os = "windows")]
+#[cfg(any(target_os = "macos",
+          target_os = "ios",
+          target_os = "windows"))]
 mod imp {
     use core::prelude::*;
     use collections::vec::Vec;
diff --git a/src/librustrt/lib.rs b/src/librustrt/lib.rs
index b4ad1f23154b4..72c7d89a3b98b 100644
--- a/src/librustrt/lib.rs
+++ b/src/librustrt/lib.rs
@@ -160,7 +160,7 @@ pub unsafe fn cleanup() {
 pub mod shouldnt_be_public {
     #[cfg(not(test))]
     pub use super::local_ptr::native::maybe_tls_key;
-    #[cfg(not(windows), not(target_os = "android"), not(target_os = "ios"))]
+    #[cfg(all(not(windows), not(target_os = "android"), not(target_os = "ios")))]
     pub use super::local_ptr::compiled::RT_TLS_PTR;
 }
 
diff --git a/src/librustrt/libunwind.rs b/src/librustrt/libunwind.rs
index aab75d7f7746d..2e7408d91591c 100644
--- a/src/librustrt/libunwind.rs
+++ b/src/librustrt/libunwind.rs
@@ -16,8 +16,7 @@
 
 use libc;
 
-#[cfg(not(target_arch = "arm"))]
-#[cfg(target_os = "ios")]
+#[cfg(any(not(target_arch = "arm"), target_os = "ios"))]
 #[repr(C)]
 pub enum _Unwind_Action {
     _UA_SEARCH_PHASE = 1,
@@ -62,14 +61,13 @@ pub static unwinder_private_data_size: uint = 5;
 #[cfg(target_arch = "x86_64")]
 pub static unwinder_private_data_size: uint = 6;
 
-#[cfg(target_arch = "arm", not(target_os = "ios"))]
+#[cfg(all(target_arch = "arm", not(target_os = "ios")))]
 pub static unwinder_private_data_size: uint = 20;
 
-#[cfg(target_arch = "arm", target_os = "ios")]
+#[cfg(all(target_arch = "arm", target_os = "ios"))]
 pub static unwinder_private_data_size: uint = 5;
 
-#[cfg(target_arch = "mips")]
-#[cfg(target_arch = "mipsel")]
+#[cfg(any(target_arch = "mips", target_arch = "mipsel"))]
 pub static unwinder_private_data_size: uint = 2;
 
 #[repr(C)]
@@ -85,8 +83,7 @@ pub type _Unwind_Exception_Cleanup_Fn =
         extern "C" fn(unwind_code: _Unwind_Reason_Code,
                       exception: *mut _Unwind_Exception);
 
-#[cfg(target_os = "linux")]
-#[cfg(target_os = "freebsd")]
+#[cfg(any(target_os = "linux", target_os = "freebsd"))]
 #[link(name = "gcc_s")]
 extern {}
 
@@ -101,11 +98,11 @@ extern {}
 extern "C" {
     // iOS on armv7 uses SjLj exceptions and requires to link
     // against corresponding routine (..._SjLj_...)
-    #[cfg(not(target_os = "ios", target_arch = "arm"))]
+    #[cfg(not(all(target_os = "ios", target_arch = "arm")))]
     pub fn _Unwind_RaiseException(exception: *mut _Unwind_Exception)
                                   -> _Unwind_Reason_Code;
 
-    #[cfg(target_os = "ios", target_arch = "arm")]
+    #[cfg(all(target_os = "ios", target_arch = "arm"))]
     fn _Unwind_SjLj_RaiseException(e: *mut _Unwind_Exception)
                                    -> _Unwind_Reason_Code;
 
@@ -115,7 +112,7 @@ extern "C" {
 // ... and now we just providing access to SjLj counterspart
 // through a standard name to hide those details from others
 // (see also comment above regarding _Unwind_RaiseException)
-#[cfg(target_os = "ios", target_arch = "arm")]
+#[cfg(all(target_os = "ios", target_arch = "arm"))]
 #[inline(always)]
 pub unsafe fn _Unwind_RaiseException(exc: *mut _Unwind_Exception)
                                      -> _Unwind_Reason_Code {
diff --git a/src/librustrt/local_ptr.rs b/src/librustrt/local_ptr.rs
index 912e4ef4d40f4..58f8f8b310f55 100644
--- a/src/librustrt/local_ptr.rs
+++ b/src/librustrt/local_ptr.rs
@@ -22,13 +22,13 @@ use core::prelude::*;
 use core::mem;
 use alloc::boxed::Box;
 
-#[cfg(windows)]               // mingw-w32 doesn't like thread_local things
-#[cfg(target_os = "android")] // see #10686
-#[cfg(target_os = "ios")]
+#[cfg(any(windows, // mingw-w32 doesn't like thread_local things
+          target_os = "android", // see #10686
+          target_os = "ios"))]
 pub use self::native::{init, cleanup, put, take, try_take, unsafe_take, exists,
                        unsafe_borrow, try_unsafe_borrow};
 
-#[cfg(not(windows), not(target_os = "android"), not(target_os = "ios"))]
+#[cfg(not(any(windows, target_os = "android", target_os = "ios")))]
 pub use self::compiled::{init, cleanup, put, take, try_take, unsafe_take, exists,
                          unsafe_borrow, try_unsafe_borrow};
 
@@ -82,7 +82,7 @@ pub unsafe fn borrow<T>() -> Borrowed<T> {
 /// implemented using LLVM's thread_local attribute which isn't necessarily
 /// working on all platforms. This implementation is faster, however, so we use
 /// it wherever possible.
-#[cfg(not(windows), not(target_os = "android"), not(target_os = "ios"))]
+#[cfg(not(any(windows, target_os = "android", target_os = "ios")))]
 pub mod compiled {
     use core::prelude::*;
 
diff --git a/src/librustrt/mutex.rs b/src/librustrt/mutex.rs
index f4fff43fd7c4f..86dc9b85a792d 100644
--- a/src/librustrt/mutex.rs
+++ b/src/librustrt/mutex.rs
@@ -346,8 +346,7 @@ mod imp {
     type pthread_mutexattr_t = libc::c_void;
     type pthread_condattr_t = libc::c_void;
 
-    #[cfg(target_os = "freebsd")]
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "freebsd", target_os = "dragonfly"))]
     mod os {
         use libc;
 
@@ -360,8 +359,7 @@ mod imp {
             0 as pthread_cond_t;
     }
 
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
+    #[cfg(any(target_os = "macos", target_os = "ios"))]
     mod os {
         use libc;
 
diff --git a/src/librustrt/stack.rs b/src/librustrt/stack.rs
index a4cbbf248113f..5c94ef61bfdb7 100644
--- a/src/librustrt/stack.rs
+++ b/src/librustrt/stack.rs
@@ -156,13 +156,13 @@ pub unsafe fn record_rust_managed_stack_bounds(stack_lo: uint, stack_hi: uint) {
     #[cfg(not(windows))] #[inline(always)]
     unsafe fn target_record_stack_bounds(_stack_lo: uint, _stack_hi: uint) {}
 
-    #[cfg(windows, target_arch = "x86")] #[inline(always)]
+    #[cfg(all(windows, target_arch = "x86"))] #[inline(always)]
     unsafe fn target_record_stack_bounds(stack_lo: uint, stack_hi: uint) {
         // stack range is at TIB: %fs:0x04 (top) and %fs:0x08 (bottom)
         asm!("mov $0, %fs:0x04" :: "r"(stack_hi) :: "volatile");
         asm!("mov $0, %fs:0x08" :: "r"(stack_lo) :: "volatile");
     }
-    #[cfg(windows, target_arch = "x86_64")] #[inline(always)]
+    #[cfg(all(windows, target_arch = "x86_64"))] #[inline(always)]
     unsafe fn target_record_stack_bounds(stack_lo: uint, stack_hi: uint) {
         // stack range is at TIB: %gs:0x08 (top) and %gs:0x10 (bottom)
         asm!("mov $0, %gs:0x08" :: "r"(stack_hi) :: "volatile");
@@ -189,49 +189,53 @@ pub unsafe fn record_sp_limit(limit: uint) {
     return target_record_sp_limit(limit);
 
     // x86-64
-    #[cfg(target_arch = "x86_64", target_os = "macos")]
-    #[cfg(target_arch = "x86_64", target_os = "ios")] #[inline(always)]
+    #[cfg(all(target_arch = "x86_64",
+              any(target_os = "macos", target_os = "ios")))]
+    #[inline(always)]
     unsafe fn target_record_sp_limit(limit: uint) {
         asm!("movq $$0x60+90*8, %rsi
               movq $0, %gs:(%rsi)" :: "r"(limit) : "rsi" : "volatile")
     }
-    #[cfg(target_arch = "x86_64", target_os = "linux")] #[inline(always)]
+    #[cfg(all(target_arch = "x86_64", target_os = "linux"))] #[inline(always)]
     unsafe fn target_record_sp_limit(limit: uint) {
         asm!("movq $0, %fs:112" :: "r"(limit) :: "volatile")
     }
-    #[cfg(target_arch = "x86_64", target_os = "windows")] #[inline(always)]
+    #[cfg(all(target_arch = "x86_64", target_os = "windows"))] #[inline(always)]
     unsafe fn target_record_sp_limit(_: uint) {
     }
-    #[cfg(target_arch = "x86_64", target_os = "freebsd")] #[inline(always)]
+    #[cfg(all(target_arch = "x86_64", target_os = "freebsd"))] #[inline(always)]
     unsafe fn target_record_sp_limit(limit: uint) {
         asm!("movq $0, %fs:24" :: "r"(limit) :: "volatile")
     }
-    #[cfg(target_arch = "x86_64", target_os = "dragonfly")] #[inline(always)]
+    #[cfg(all(target_arch = "x86_64", target_os = "dragonfly"))] #[inline(always)]
     unsafe fn target_record_sp_limit(limit: uint) {
         asm!("movq $0, %fs:32" :: "r"(limit) :: "volatile")
     }
 
     // x86
-    #[cfg(target_arch = "x86", target_os = "macos")]
-    #[cfg(target_arch = "x86", target_os = "ios")] #[inline(always)]
+    #[cfg(all(target_arch = "x86",
+              any(target_os = "macos", target_os = "ios")))]
+    #[inline(always)]
     unsafe fn target_record_sp_limit(limit: uint) {
         asm!("movl $$0x48+90*4, %eax
               movl $0, %gs:(%eax)" :: "r"(limit) : "eax" : "volatile")
     }
-    #[cfg(target_arch = "x86", target_os = "linux")]
-    #[cfg(target_arch = "x86", target_os = "freebsd")] #[inline(always)]
+    #[cfg(all(target_arch = "x86",
+              any(target_os = "linux", target_os = "freebsd")))]
+    #[inline(always)]
     unsafe fn target_record_sp_limit(limit: uint) {
         asm!("movl $0, %gs:48" :: "r"(limit) :: "volatile")
     }
-    #[cfg(target_arch = "x86", target_os = "windows")] #[inline(always)]
+    #[cfg(all(target_arch = "x86", target_os = "windows"))] #[inline(always)]
     unsafe fn target_record_sp_limit(_: uint) {
     }
 
     // mips, arm - Some brave soul can port these to inline asm, but it's over
     //             my head personally
-    #[cfg(target_arch = "mips")]
-    #[cfg(target_arch = "mipsel")]
-    #[cfg(target_arch = "arm", not(target_os = "ios"))] #[inline(always)]
+    #[cfg(any(target_arch = "mips",
+              target_arch = "mipsel",
+              all(target_arch = "arm", not(target_os = "ios"))))]
+    #[inline(always)]
     unsafe fn target_record_sp_limit(limit: uint) {
         use libc::c_void;
         return record_sp_limit(limit as *const c_void);
@@ -241,7 +245,7 @@ pub unsafe fn record_sp_limit(limit: uint) {
     }
 
     // iOS segmented stack is disabled for now, see related notes
-    #[cfg(target_arch = "arm", target_os = "ios")] #[inline(always)]
+    #[cfg(all(target_arch = "arm", target_os = "ios"))] #[inline(always)]
     unsafe fn target_record_sp_limit(_: uint) {
     }
 }
@@ -259,31 +263,32 @@ pub unsafe fn get_sp_limit() -> uint {
     return target_get_sp_limit();
 
     // x86-64
-    #[cfg(target_arch = "x86_64", target_os = "macos")]
-    #[cfg(target_arch = "x86_64", target_os = "ios")] #[inline(always)]
+    #[cfg(all(target_arch = "x86_64",
+              any(target_os = "macos", target_os = "ios")))]
+    #[inline(always)]
     unsafe fn target_get_sp_limit() -> uint {
         let limit;
         asm!("movq $$0x60+90*8, %rsi
               movq %gs:(%rsi), $0" : "=r"(limit) :: "rsi" : "volatile");
         return limit;
     }
-    #[cfg(target_arch = "x86_64", target_os = "linux")] #[inline(always)]
+    #[cfg(all(target_arch = "x86_64", target_os = "linux"))] #[inline(always)]
     unsafe fn target_get_sp_limit() -> uint {
         let limit;
         asm!("movq %fs:112, $0" : "=r"(limit) ::: "volatile");
         return limit;
     }
-    #[cfg(target_arch = "x86_64", target_os = "windows")] #[inline(always)]
+    #[cfg(all(target_arch = "x86_64", target_os = "windows"))] #[inline(always)]
     unsafe fn target_get_sp_limit() -> uint {
         return 1024;
     }
-    #[cfg(target_arch = "x86_64", target_os = "freebsd")] #[inline(always)]
+    #[cfg(all(target_arch = "x86_64", target_os = "freebsd"))] #[inline(always)]
     unsafe fn target_get_sp_limit() -> uint {
         let limit;
         asm!("movq %fs:24, $0" : "=r"(limit) ::: "volatile");
         return limit;
     }
-    #[cfg(target_arch = "x86_64", target_os = "dragonfly")] #[inline(always)]
+    #[cfg(all(target_arch = "x86_64", target_os = "dragonfly"))] #[inline(always)]
     unsafe fn target_get_sp_limit() -> uint {
         let limit;
         asm!("movq %fs:32, $0" : "=r"(limit) ::: "volatile");
@@ -292,31 +297,34 @@ pub unsafe fn get_sp_limit() -> uint {
 
 
     // x86
-    #[cfg(target_arch = "x86", target_os = "macos")]
-    #[cfg(target_arch = "x86", target_os = "ios")] #[inline(always)]
+    #[cfg(all(target_arch = "x86",
+              any(target_os = "macos", target_os = "ios")))]
+    #[inline(always)]
     unsafe fn target_get_sp_limit() -> uint {
         let limit;
         asm!("movl $$0x48+90*4, %eax
               movl %gs:(%eax), $0" : "=r"(limit) :: "eax" : "volatile");
         return limit;
     }
-    #[cfg(target_arch = "x86", target_os = "linux")]
-    #[cfg(target_arch = "x86", target_os = "freebsd")] #[inline(always)]
+    #[cfg(all(target_arch = "x86",
+              any(target_os = "linux", target_os = "freebsd")))]
+    #[inline(always)]
     unsafe fn target_get_sp_limit() -> uint {
         let limit;
         asm!("movl %gs:48, $0" : "=r"(limit) ::: "volatile");
         return limit;
     }
-    #[cfg(target_arch = "x86", target_os = "windows")] #[inline(always)]
+    #[cfg(all(target_arch = "x86", target_os = "windows"))] #[inline(always)]
     unsafe fn target_get_sp_limit() -> uint {
         return 1024;
     }
 
     // mips, arm - Some brave soul can port these to inline asm, but it's over
     //             my head personally
-    #[cfg(target_arch = "mips")]
-    #[cfg(target_arch = "mipsel")]
-    #[cfg(target_arch = "arm", not(target_os = "ios"))] #[inline(always)]
+    #[cfg(any(target_arch = "mips",
+              target_arch = "mipsel",
+              all(target_arch = "arm", not(target_os = "ios"))))]
+    #[inline(always)]
     unsafe fn target_get_sp_limit() -> uint {
         use libc::c_void;
         return get_sp_limit() as uint;
@@ -328,7 +336,7 @@ pub unsafe fn get_sp_limit() -> uint {
     // iOS doesn't support segmented stacks yet. This function might
     // be called by runtime though so it is unsafe to mark it as
     // unreachable, let's return a fixed constant.
-    #[cfg(target_arch = "arm", target_os = "ios")] #[inline(always)]
+    #[cfg(all(target_arch = "arm", target_os = "ios"))] #[inline(always)]
     unsafe fn target_get_sp_limit() -> uint {
         1024
     }
diff --git a/src/librustrt/thread_local_storage.rs b/src/librustrt/thread_local_storage.rs
index 6078ed990e41d..aee70980bbaf7 100644
--- a/src/librustrt/thread_local_storage.rs
+++ b/src/librustrt/thread_local_storage.rs
@@ -41,11 +41,11 @@ pub unsafe fn destroy(key: Key) {
 #[allow(non_camel_case_types)] // foreign type
 type pthread_key_t = ::libc::c_ulong;
 
-#[cfg(target_os="linux")]
-#[cfg(target_os="freebsd")]
-#[cfg(target_os="dragonfly")]
-#[cfg(target_os="android")]
-#[cfg(target_os = "ios")]
+#[cfg(any(target_os="linux",
+          target_os="freebsd",
+          target_os="dragonfly",
+          target_os="android",
+          target_os = "ios"))]
 #[allow(non_camel_case_types)] // foreign type
 type pthread_key_t = ::libc::c_uint;
 
diff --git a/src/librustrt/unwind.rs b/src/librustrt/unwind.rs
index d3ab0f27c1328..1561f428ce548 100644
--- a/src/librustrt/unwind.rs
+++ b/src/librustrt/unwind.rs
@@ -235,7 +235,9 @@ fn rust_exception_class() -> uw::_Unwind_Exception_Class {
 //
 // See also: rt/rust_try.ll
 
-#[cfg(not(target_arch = "arm"), not(windows, target_arch = "x86_64"), not(test))]
+#[cfg(all(not(target_arch = "arm"),
+          not(all(windows, target_arch = "x86_64")),
+          not(test)))]
 #[doc(hidden)]
 pub mod eabi {
     use libunwind as uw;
@@ -288,7 +290,7 @@ pub mod eabi {
 // iOS on armv7 is using SjLj exceptions and therefore requires to use
 // a specialized personality routine: __gcc_personality_sj0
 
-#[cfg(target_os = "ios", target_arch = "arm", not(test))]
+#[cfg(all(target_os = "ios", target_arch = "arm", not(test)))]
 #[doc(hidden)]
 pub mod eabi {
     use libunwind as uw;
@@ -343,7 +345,7 @@ pub mod eabi {
 
 // ARM EHABI uses a slightly different personality routine signature,
 // but otherwise works the same.
-#[cfg(target_arch = "arm", not(target_os = "ios"), not(test))]
+#[cfg(all(target_arch = "arm", not(target_os = "ios"), not(test)))]
 #[doc(hidden)]
 pub mod eabi {
     use libunwind as uw;
@@ -392,7 +394,7 @@ pub mod eabi {
 // GCC reuses the same personality routine as for the other architectures by wrapping it
 // with an "API translator" layer (_GCC_specific_handler).
 
-#[cfg(windows, target_arch = "x86_64", not(test))]
+#[cfg(all(windows, target_arch = "x86_64", not(test)))]
 #[doc(hidden)]
 #[allow(non_camel_case_types, non_snake_case)]
 pub mod eabi {
diff --git a/src/librustuv/uvll.rs b/src/librustuv/uvll.rs
index c7c278675c182..35bd20c0dd90b 100644
--- a/src/librustuv/uvll.rs
+++ b/src/librustuv/uvll.rs
@@ -723,12 +723,11 @@ extern {
 
 // libuv doesn't use pthread on windows
 // android libc (bionic) provides pthread, so no additional link is required
-#[cfg(not(windows), not(target_os = "android"))]
+#[cfg(not(any(windows, target_os = "android")))]
 #[link(name = "pthread")]
 extern {}
 
-#[cfg(target_os = "linux")]
-#[cfg(target_os = "dragonfly")]
+#[cfg(any(target_os = "linux", target_os = "dragonfly"))]
 #[link(name = "rt")]
 extern {}
 
@@ -738,7 +737,6 @@ extern {}
 #[link(name = "iphlpapi")]
 extern {}
 
-#[cfg(target_os = "freebsd")]
-#[cfg(target_os = "dragonfly")]
+#[cfg(any(target_os = "freebsd", target_os = "dragonfly"))]
 #[link(name = "kvm")]
 extern {}
diff --git a/src/libstd/dynamic_lib.rs b/src/libstd/dynamic_lib.rs
index a88448f47e0c6..bd2bd1ad0904a 100644
--- a/src/libstd/dynamic_lib.rs
+++ b/src/libstd/dynamic_lib.rs
@@ -154,7 +154,7 @@ impl DynamicLibrary {
     }
 }
 
-#[cfg(test, not(target_os = "ios"))]
+#[cfg(all(test, not(target_os = "ios")))]
 mod test {
     use super::*;
     use prelude::*;
@@ -189,10 +189,10 @@ mod test {
     }
 
     #[test]
-    #[cfg(target_os = "linux")]
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "freebsd")]
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "linux",
+              target_os = "macos",
+              target_os = "freebsd",
+              target_os = "dragonfly"))]
     fn test_errors_do_not_crash() {
         // Open /dev/null as a library to get an error, and make sure
         // that only causes an error, and not a crash.
@@ -204,12 +204,12 @@ mod test {
     }
 }
 
-#[cfg(target_os = "linux")]
-#[cfg(target_os = "android")]
-#[cfg(target_os = "macos")]
-#[cfg(target_os = "ios")]
-#[cfg(target_os = "freebsd")]
-#[cfg(target_os = "dragonfly")]
+#[cfg(any(target_os = "linux",
+          target_os = "android",
+          target_os = "macos",
+          target_os = "ios",
+          target_os = "freebsd",
+          target_os = "dragonfly"))]
 pub mod dl {
 
     use c_str::{CString, ToCStr};
diff --git a/src/libstd/io/net/addrinfo.rs b/src/libstd/io/net/addrinfo.rs
index 867e8bcca826d..ea1dd12f323a7 100644
--- a/src/libstd/io/net/addrinfo.rs
+++ b/src/libstd/io/net/addrinfo.rs
@@ -123,7 +123,7 @@ fn lookup(hostname: Option<&str>, servname: Option<&str>, hint: Option<Hint>)
 
 // Ignored on android since we cannot give tcp/ip
 // permission without help of apk
-#[cfg(test, not(target_os = "android"))]
+#[cfg(all(test, not(target_os = "android")))]
 mod test {
     iotest!(fn dns_smoke_test() {
         let ipaddrs = get_host_addresses("localhost").unwrap();
diff --git a/src/libstd/io/process.rs b/src/libstd/io/process.rs
index 83890d2b1275e..f97e9f4647ba0 100644
--- a/src/libstd/io/process.rs
+++ b/src/libstd/io/process.rs
@@ -693,7 +693,7 @@ mod tests {
         drop(p.wait().clone());
     })
 
-    #[cfg(unix, not(target_os="android"))]
+    #[cfg(all(unix, not(target_os="android")))]
     iotest!(fn signal_reported_right() {
         let p = Command::new("/bin/sh").arg("-c").arg("kill -1 $$").spawn();
         assert!(p.is_ok());
@@ -725,7 +725,7 @@ mod tests {
         assert_eq!(run_output(cmd), "foobar\n".to_string());
     })
 
-    #[cfg(unix, not(target_os="android"))]
+    #[cfg(all(unix, not(target_os="android")))]
     iotest!(fn set_cwd_works() {
         let mut cmd = Command::new("/bin/sh");
         cmd.arg("-c").arg("pwd")
@@ -734,7 +734,7 @@ mod tests {
         assert_eq!(run_output(cmd), "/\n".to_string());
     })
 
-    #[cfg(unix, not(target_os="android"))]
+    #[cfg(all(unix, not(target_os="android")))]
     iotest!(fn stdin_works() {
         let mut p = Command::new("/bin/sh")
                             .arg("-c").arg("read line; echo $line")
@@ -759,7 +759,7 @@ mod tests {
         assert!(Command::new("test").uid(10).spawn().is_err());
     })
 
-    #[cfg(unix, not(target_os="android"))]
+    #[cfg(all(unix, not(target_os="android")))]
     iotest!(fn uid_works() {
         use libc;
         let mut p = Command::new("/bin/sh")
@@ -770,7 +770,7 @@ mod tests {
         assert!(p.wait().unwrap().success());
     })
 
-    #[cfg(unix, not(target_os="android"))]
+    #[cfg(all(unix, not(target_os="android")))]
     iotest!(fn uid_to_root_fails() {
         use libc;
 
@@ -847,7 +847,7 @@ mod tests {
         }
     })
 
-    #[cfg(unix,not(target_os="android"))]
+    #[cfg(all(unix, not(target_os="android")))]
     pub fn pwd_cmd() -> Command {
         Command::new("pwd")
     }
@@ -897,7 +897,7 @@ mod tests {
         assert_eq!(parent_stat.unstable.inode, child_stat.unstable.inode);
     })
 
-    #[cfg(unix,not(target_os="android"))]
+    #[cfg(all(unix, not(target_os="android")))]
     pub fn env_cmd() -> Command {
         Command::new("env")
     }
diff --git a/src/libstd/io/signal.rs b/src/libstd/io/signal.rs
index 1d882bdc0ad9e..79a00e90b4074 100644
--- a/src/libstd/io/signal.rs
+++ b/src/libstd/io/signal.rs
@@ -160,7 +160,7 @@ impl Listener {
     }
 }
 
-#[cfg(test, unix)]
+#[cfg(all(test, unix))]
 mod test_unix {
     use prelude::*;
     use libc;
@@ -218,7 +218,7 @@ mod test_unix {
     }
 }
 
-#[cfg(test, windows)]
+#[cfg(all(test, windows))]
 mod test_windows {
     use super::{User1, Listener};
     use result::{Ok, Err};
diff --git a/src/libstd/os.rs b/src/libstd/os.rs
index 478a40f17b0d3..d904e657e403b 100644
--- a/src/libstd/os.rs
+++ b/src/libstd/os.rs
@@ -653,8 +653,7 @@ pub fn dll_filename(base: &str) -> String {
 /// ```
 pub fn self_exe_name() -> Option<Path> {
 
-    #[cfg(target_os = "freebsd")]
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "freebsd", target_os = "dragonfly"))]
     fn load_self() -> Option<Vec<u8>> {
         unsafe {
             use libc::funcs::bsd44::*;
@@ -680,8 +679,7 @@ pub fn self_exe_name() -> Option<Path> {
         }
     }
 
-    #[cfg(target_os = "linux")]
-    #[cfg(target_os = "android")]
+    #[cfg(any(target_os = "linux", target_os = "android"))]
     fn load_self() -> Option<Vec<u8>> {
         use std::io;
 
@@ -691,8 +689,7 @@ pub fn self_exe_name() -> Option<Path> {
         }
     }
 
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
+    #[cfg(any(target_os = "macos", target_os = "ios"))]
     fn load_self() -> Option<Vec<u8>> {
         unsafe {
             use libc::funcs::extra::_NSGetExecutablePath;
@@ -909,9 +906,9 @@ pub fn change_dir(p: &Path) -> bool {
 #[cfg(unix)]
 /// Returns the platform-specific value of errno
 pub fn errno() -> int {
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
-    #[cfg(target_os = "freebsd")]
+    #[cfg(any(target_os = "macos",
+              target_os = "ios",
+              target_os = "freebsd"))]
     fn errno_location() -> *const c_int {
         extern {
             fn __error() -> *const c_int;
@@ -931,8 +928,7 @@ pub fn errno() -> int {
         }
     }
 
-    #[cfg(target_os = "linux")]
-    #[cfg(target_os = "android")]
+    #[cfg(any(target_os = "linux", target_os = "android"))]
     fn errno_location() -> *const c_int {
         extern {
             fn __errno_location() -> *const c_int;
@@ -975,11 +971,11 @@ pub fn error_string(errnum: uint) -> String {
 
     #[cfg(unix)]
     fn strerror(errnum: uint) -> String {
-        #[cfg(target_os = "macos")]
-        #[cfg(target_os = "ios")]
-        #[cfg(target_os = "android")]
-        #[cfg(target_os = "freebsd")]
-        #[cfg(target_os = "dragonfly")]
+        #[cfg(any(target_os = "macos",
+                  target_os = "ios",
+                  target_os = "android",
+                  target_os = "freebsd",
+                  target_os = "dragonfly"))]
         fn strerror_r(errnum: c_int, buf: *mut c_char, buflen: libc::size_t)
                       -> c_int {
             extern {
@@ -1180,10 +1176,10 @@ fn real_args_as_bytes() -> Vec<Vec<u8>> {
     res
 }
 
-#[cfg(target_os = "linux")]
-#[cfg(target_os = "android")]
-#[cfg(target_os = "freebsd")]
-#[cfg(target_os = "dragonfly")]
+#[cfg(any(target_os = "linux",
+          target_os = "android",
+          target_os = "freebsd",
+          target_os = "dragonfly"))]
 fn real_args_as_bytes() -> Vec<Vec<u8>> {
     use rt;
 
diff --git a/src/libstd/rand/os.rs b/src/libstd/rand/os.rs
index 120ace1c36a5f..c5b7154ffdb57 100644
--- a/src/libstd/rand/os.rs
+++ b/src/libstd/rand/os.rs
@@ -13,7 +13,7 @@
 
 pub use self::imp::OsRng;
 
-#[cfg(unix, not(target_os = "ios"))]
+#[cfg(all(unix, not(target_os = "ios")))]
 mod imp {
     use io::{IoResult, File};
     use path::Path;
diff --git a/src/libstd/rt/backtrace.rs b/src/libstd/rt/backtrace.rs
index aa9505d83fc27..33f8713e1a13c 100644
--- a/src/libstd/rt/backtrace.rs
+++ b/src/libstd/rt/backtrace.rs
@@ -253,7 +253,7 @@ mod imp {
     /// play well with green threads, so while it is extremely nice
     /// and simple to use it should be used only on iOS devices as the
     /// only viable option.
-    #[cfg(target_os = "ios", target_arch = "arm")]
+    #[cfg(all(target_os = "ios", target_arch = "arm"))]
     #[inline(never)]
     pub fn write(w: &mut Writer) -> IoResult<()> {
         use iter::{Iterator, range};
@@ -284,7 +284,7 @@ mod imp {
         result::fold(iter, (), |_, _| ())
     }
 
-    #[cfg(not(target_os = "ios", target_arch = "arm"))]
+    #[cfg(not(all(target_os = "ios", target_arch = "arm")))]
     #[inline(never)] // if we know this is a function call, we can skip it when
                      // tracing
     pub fn write(w: &mut Writer) -> IoResult<()> {
@@ -365,8 +365,7 @@ mod imp {
         }
     }
 
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
+    #[cfg(any(target_os = "macos", target_os = "ios"))]
     fn print(w: &mut Writer, idx: int, addr: *mut libc::c_void) -> IoResult<()> {
         use intrinsics;
         #[repr(C)]
@@ -391,7 +390,7 @@ mod imp {
         }
     }
 
-    #[cfg(not(target_os = "macos"), not(target_os = "ios"))]
+    #[cfg(not(any(target_os = "macos", target_os = "ios")))]
     fn print(w: &mut Writer, idx: int, addr: *mut libc::c_void) -> IoResult<()> {
         use collections::Collection;
         use iter::Iterator;
@@ -571,16 +570,17 @@ mod imp {
 
         extern {
             // No native _Unwind_Backtrace on iOS
-            #[cfg(not(target_os = "ios", target_arch = "arm"))]
+            #[cfg(not(all(target_os = "ios", target_arch = "arm")))]
             pub fn _Unwind_Backtrace(trace: _Unwind_Trace_Fn,
                                      trace_argument: *mut libc::c_void)
                         -> _Unwind_Reason_Code;
 
-            #[cfg(not(target_os = "android"),
-                  not(target_os = "linux", target_arch = "arm"))]
+            #[cfg(all(not(target_os = "android"),
+                      not(all(target_os = "linux", target_arch = "arm"))))]
             pub fn _Unwind_GetIP(ctx: *mut _Unwind_Context) -> libc::uintptr_t;
-            #[cfg(not(target_os = "android"),
-                  not(target_os = "linux", target_arch = "arm"))]
+
+            #[cfg(all(not(target_os = "android"),
+                      not(all(target_os = "linux", target_arch = "arm"))))]
             pub fn _Unwind_FindEnclosingFunction(pc: *mut libc::c_void)
                 -> *mut libc::c_void;
         }
@@ -588,8 +588,8 @@ mod imp {
         // On android, the function _Unwind_GetIP is a macro, and this is the
         // expansion of the macro. This is all copy/pasted directly from the
         // header file with the definition of _Unwind_GetIP.
-        #[cfg(target_os = "android")]
-        #[cfg(target_os = "linux", target_arch = "arm")]
+        #[cfg(any(target_os = "android",
+                  all(target_os = "linux", target_arch = "arm")))]
         pub unsafe fn _Unwind_GetIP(ctx: *mut _Unwind_Context) -> libc::uintptr_t {
             #[repr(C)]
             enum _Unwind_VRS_Result {
@@ -634,8 +634,8 @@ mod imp {
 
         // This function also doesn't exist on Android or ARM/Linux, so make it
         // a no-op
-        #[cfg(target_os = "android")]
-        #[cfg(target_os = "linux", target_arch = "arm")]
+        #[cfg(any(target_os = "android",
+                  all(target_os = "linux", target_arch = "arm")))]
         pub unsafe fn _Unwind_FindEnclosingFunction(pc: *mut libc::c_void)
             -> *mut libc::c_void
         {
diff --git a/src/libsyntax/attr.rs b/src/libsyntax/attr.rs
index 8963185192a8b..1491f02b3f5c1 100644
--- a/src/libsyntax/attr.rs
+++ b/src/libsyntax/attr.rs
@@ -315,14 +315,11 @@ pub fn cfg_matches(diagnostic: &SpanHandler, cfgs: &[P<MetaItem>], cfg: &ast::Me
         ast::MetaList(ref pred, ref mis) if pred.get() == "all" =>
             mis.iter().all(|mi| cfg_matches(diagnostic, cfgs, &**mi)),
         ast::MetaList(ref pred, ref mis) if pred.get() == "not" => {
-            // NOTE: turn on after snapshot
-            /*
             if mis.len() != 1 {
                 diagnostic.span_warn(cfg.span, "the use of multiple cfgs in the same `not` \
                                                 statement is deprecated. Change `not(a, b)` to \
                                                 `not(all(a, b))`.");
             }
-            */
             !mis.iter().all(|mi| cfg_matches(diagnostic, cfgs, &**mi))
         }
         ast::MetaList(ref pred, _) => {
diff --git a/src/libsyntax/config.rs b/src/libsyntax/config.rs
index 5b17f6f004a08..c5ef2399b1a9f 100644
--- a/src/libsyntax/config.rs
+++ b/src/libsyntax/config.rs
@@ -260,8 +260,6 @@ fn in_cfg(diagnostic: &SpanHandler, cfg: &[P<ast::MetaItem>], attrs: &[ast::Attr
             _ => continue
         };
 
-        // NOTE: turn on after snapshot
-        /*
         if mis.len() != 1 {
             diagnostic.span_warn(attr.span, "The use of multiple cfgs in the top level of \
                                              `#[cfg(..)]` is deprecated. Change `#[cfg(a, b)]` to \
@@ -274,7 +272,6 @@ fn in_cfg(diagnostic: &SpanHandler, cfg: &[P<ast::MetaItem>], attrs: &[ast::Attr
                                              the intersection of the cfgs. Change `#[cfg(a)] \
                                              #[cfg(b)]` to `#[cfg(any(a, b))]`.");
         }
-        */
 
         seen_cfg = true;
         in_cfg |= mis.iter().all(|mi| attr::cfg_matches(diagnostic, cfg, &**mi));
diff --git a/src/libsyntax/ext/cfg.rs b/src/libsyntax/ext/cfg.rs
index 342e7e6d52e84..74039da6cabdb 100644
--- a/src/libsyntax/ext/cfg.rs
+++ b/src/libsyntax/ext/cfg.rs
@@ -38,14 +38,11 @@ pub fn expand_cfg<'cx>(cx: &mut ExtCtxt,
         p.expect(&token::COMMA);
     }
 
-    // NOTE: turn on after snapshot
-    /*
     if cfgs.len() != 1 {
         cx.span_warn(sp, "The use of multiple cfgs at the top level of `cfg!` \
                           is deprecated. Change `cfg!(a, b)` to \
                           `cfg!(all(a, b))`.");
     }
-    */
 
     let matches_cfg = cfgs.iter().all(|cfg| attr::cfg_matches(&cx.parse_sess.span_diagnostic,
                                                               cx.cfg.as_slice(), &**cfg));
diff --git a/src/libtime/lib.rs b/src/libtime/lib.rs
index 9cec71104d403..c1889af034355 100644
--- a/src/libtime/lib.rs
+++ b/src/libtime/lib.rs
@@ -47,7 +47,7 @@ mod rustrt {
     }
 }
 
-#[cfg(unix, not(target_os = "macos"), not(target_os = "ios"))]
+#[cfg(all(unix, not(target_os = "macos"), not(target_os = "ios")))]
 mod imp {
     use libc::{c_int, timespec};
 
@@ -61,8 +61,7 @@ mod imp {
     }
 
 }
-#[cfg(target_os = "macos")]
-#[cfg(target_os = "ios")]
+#[cfg(any(target_os = "macos", target_os = "ios"))]
 mod imp {
     use libc::{timeval, timezone, c_int, mach_timebase_info};
 
@@ -150,8 +149,7 @@ pub fn get_time() -> Timespec {
          ((ns_since_1970 % 1000000) * 1000) as i32)
     }
 
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
+    #[cfg(any(target_os = "macos", target_os = "ios"))]
     unsafe fn os_get_time() -> (i64, i32) {
         use std::ptr;
         let mut tv = libc::timeval { tv_sec: 0, tv_usec: 0 };
@@ -159,7 +157,7 @@ pub fn get_time() -> Timespec {
         (tv.tv_sec as i64, tv.tv_usec * 1000)
     }
 
-    #[cfg(not(target_os = "macos"), not(target_os = "ios"), not(windows))]
+    #[cfg(not(any(target_os = "macos", target_os = "ios", windows)))]
     unsafe fn os_get_time() -> (i64, i32) {
         let mut tv = libc::timespec { tv_sec: 0, tv_nsec: 0 };
         imp::clock_gettime(libc::CLOCK_REALTIME, &mut tv);
@@ -190,8 +188,7 @@ pub fn precise_time_ns() -> u64 {
         return (ticks as u64 * 1000000000) / (ticks_per_s as u64);
     }
 
-    #[cfg(target_os = "macos")]
-    #[cfg(target_os = "ios")]
+    #[cfg(any(target_os = "macos", target_os = "ios"))]
     fn os_precise_time_ns() -> u64 {
         static mut TIMEBASE: libc::mach_timebase_info = libc::mach_timebase_info { numer: 0,
                                                                                    denom: 0 };
@@ -205,7 +202,7 @@ pub fn precise_time_ns() -> u64 {
         }
     }
 
-    #[cfg(not(windows), not(target_os = "macos"), not(target_os = "ios"))]
+    #[cfg(not(any(windows, target_os = "macos", target_os = "ios")))]
     fn os_precise_time_ns() -> u64 {
         let mut ts = libc::timespec { tv_sec: 0, tv_nsec: 0 };
         unsafe {