Deprecate vfork

Author: Amanieu

src/unix/linux_like/mod.rs

@@ -1458,6 +1458,10 @@ extern "C" {
     pub fn acct(filename: *const ::c_char) -> ::c_int;
     pub fn brk(addr: *mut ::c_void) -> ::c_int;
     pub fn sbrk(increment: ::intptr_t) -> *mut ::c_void;
+    #[deprecated(
+        since = "0.2.65",
+        note = "generates incorrect code due to the lack of #[returns_twice]"
+    )]
     pub fn vfork() -> ::pid_t;
     pub fn setresgid(rgid: ::gid_t, egid: ::gid_t, sgid: ::gid_t) -> ::c_int;
     pub fn setresuid(ruid: ::uid_t, euid: ::uid_t, suid: ::uid_t) -> ::c_int;