Fix ioctl constants for musl target envs.

According to musl's source, the `ioctl` [function
signature][musl-ioctl-h] takes an `int` as the request argument (i.e. an
`i32`) which is reflected in this crate's [ioctl
binding][musl-ioctl-rs]. It looks like when the ioctl constants were
added that [glibc's default][glibc-ioctl-h] of a `c_ulong` type was used
for the musl values as well, rather than a `c_int` type. This change
updates these constants to a `c_int` so that they match the expected
function call type.

Here is a minimal reproduction of the issue. Given this Rust program:

```rust
extern crate libc;

use libc::{ioctl, winsize, STDOUT_FILENO, TIOCGWINSZ};

fn main() {
    let mut wsize = winsize {
        ws_row: 0,
        ws_col: 0,
        ws_xpixel: 0,
        ws_ypixel: 0,
    };
    unsafe {
        ioctl(STDOUT_FILENO, TIOCGWINSZ, &mut wsize);
    }
    println!("Sizes: {{ rows: {}, cols: {}, xpixel: {}, ypixel: {} }}",
             wsize.ws_row,
             wsize.ws_col,
             wsize.ws_xpixel,
             wsize.ws_ypixel);
}
```

When run against the `x86_64-unknwon-linux-gnu` and
`x86_64-unknown-linux-musl` targets, we see the difference in behavior:

```
> cargo clean

> cargo run --target=x86_64-unknown-linux-gnu
   Compiling libc v0.2.11
   Compiling libc-musl-ioctl v0.1.0 (file:///src/libc-musl-ioctl)
     Running `target/x86_64-unknown-linux-gnu/debug/libc-musl-ioctl`
Sizes: { rows: 28, cols: 211, xpixel: 0, ypixel: 0 }

> cargo clean

> cargo run --target=x86_64-unknown-linux-musl
   Compiling libc v0.2.11
   Compiling libc-musl-ioctl v0.1.0 (file:///src/libc-musl-ioctl)
src/main.rs:13:30: 13:40 error: mismatched types:
 expected `i32`,
    found `u64` [E0308]
src/main.rs:13         ioctl(STDOUT_FILENO, TIOCGWINSZ, &mut wsize);
                                            ^~~~~~~~~~
src/main.rs:13:30: 13:40 help: run `rustc --explain E0308` to see a detailed explanation
error: aborting due to previous error
Could not compile `libc-musl-ioctl`.

To learn more, run the command again with --verbose.
```

Working against this fix:

```
> cargo clean

> cargo run --target=x86_64-unknown-linux-gnu
    Updating git repository `https://github.com/fnichol/rust-lang-libc.git`
   Compiling libc v0.2.11 (https://github.com/fnichol/rust-lang-libc.git?branch=fix-musl-ioctl-constants#3285f387)
   Compiling libc-musl-ioctl v0.1.0 (file:///src/libc-musl-ioctl)
     Running `target/x86_64-unknown-linux-gnu/debug/libc-musl-ioctl`
Sizes: { rows: 28, cols: 211, xpixel: 0, ypixel: 0 }

> cargo clean

> cargo run --target=x86_64-unknown-linux-musl
   Compiling libc v0.2.11 (https://github.com/fnichol/rust-lang-libc.git?branch=fix-musl-ioctl-constants#3285f387)
   Compiling libc-musl-ioctl v0.1.0 (file:///src/libc-musl-ioctl)
     Running `target/x86_64-unknown-linux-musl/debug/libc-musl-ioctl`
Sizes: { rows: 28, cols: 211, xpixel: 0, ypixel: 0 }
```

[musl-ioctl-rs]:
https://doc.rust-lang.org/libc/x86_64-unknown-linux-musl/libc/fn.ioctl.html

[musl-ioctl-h]:
https://git.musl-libc.org/cgit/musl/tree/include/sys/ioctl.h

[glibc-ioctl-h]:
http://bazaar.launchpad.net/~vcs-imports/glibc/master/view/head:/include/sys/ioctl.h

Author: fnichol

src/unix/notbsd/linux/musl/b32/x86.rs

@@ -286,36 +286,36 @@ pub const IEXTEN: ::tcflag_t = 0x00008000;
 pub const TOSTOP: ::tcflag_t = 0x00000100;
 pub const FLUSHO: ::tcflag_t = 0x00001000;
 
-pub const TCGETS: ::c_ulong = 0x5401;
-pub const TCSETS: ::c_ulong = 0x5402;
-pub const TCSETSW: ::c_ulong = 0x5403;
-pub const TCSETSF: ::c_ulong = 0x5404;
-pub const TCGETA: ::c_ulong = 0x5405;
-pub const TCSETA: ::c_ulong = 0x5406;
-pub const TCSETAW: ::c_ulong = 0x5407;
-pub const TCSETAF: ::c_ulong = 0x5408;
-pub const TCSBRK: ::c_ulong = 0x5409;
-pub const TCXONC: ::c_ulong = 0x540A;
-pub const TCFLSH: ::c_ulong = 0x540B;
-pub const TIOCGSOFTCAR: ::c_ulong = 0x5419;
-pub const TIOCSSOFTCAR: ::c_ulong = 0x541A;
-pub const TIOCLINUX: ::c_ulong = 0x541C;
-pub const TIOCGSERIAL: ::c_ulong = 0x541E;
-pub const TIOCEXCL: ::c_ulong = 0x540C;
-pub const TIOCNXCL: ::c_ulong = 0x540D;
-pub const TIOCSCTTY: ::c_ulong = 0x540E;
-pub const TIOCGPGRP: ::c_ulong = 0x540F;
-pub const TIOCSPGRP: ::c_ulong = 0x5410;
-pub const TIOCOUTQ: ::c_ulong = 0x5411;
-pub const TIOCSTI: ::c_ulong = 0x5412;
-pub const TIOCGWINSZ: ::c_ulong = 0x5413;
-pub const TIOCSWINSZ: ::c_ulong = 0x5414;
-pub const TIOCMGET: ::c_ulong = 0x5415;
-pub const TIOCMBIS: ::c_ulong = 0x5416;
-pub const TIOCMBIC: ::c_ulong = 0x5417;
-pub const TIOCMSET: ::c_ulong = 0x5418;
-pub const FIONREAD: ::c_ulong = 0x541B;
-pub const TIOCCONS: ::c_ulong = 0x541D;
+pub const TCGETS: ::c_int = 0x5401;
+pub const TCSETS: ::c_int = 0x5402;
+pub const TCSETSW: ::c_int = 0x5403;
+pub const TCSETSF: ::c_int = 0x5404;
+pub const TCGETA: ::c_int = 0x5405;
+pub const TCSETA: ::c_int = 0x5406;
+pub const TCSETAW: ::c_int = 0x5407;
+pub const TCSETAF: ::c_int = 0x5408;
+pub const TCSBRK: ::c_int = 0x5409;
+pub const TCXONC: ::c_int = 0x540A;
+pub const TCFLSH: ::c_int = 0x540B;
+pub const TIOCGSOFTCAR: ::c_int = 0x5419;
+pub const TIOCSSOFTCAR: ::c_int = 0x541A;
+pub const TIOCLINUX: ::c_int = 0x541C;
+pub const TIOCGSERIAL: ::c_int = 0x541E;
+pub const TIOCEXCL: ::c_int = 0x540C;
+pub const TIOCNXCL: ::c_int = 0x540D;
+pub const TIOCSCTTY: ::c_int = 0x540E;
+pub const TIOCGPGRP: ::c_int = 0x540F;
+pub const TIOCSPGRP: ::c_int = 0x5410;
+pub const TIOCOUTQ: ::c_int = 0x5411;
+pub const TIOCSTI: ::c_int = 0x5412;
+pub const TIOCGWINSZ: ::c_int = 0x5413;
+pub const TIOCSWINSZ: ::c_int = 0x5414;
+pub const TIOCMGET: ::c_int = 0x5415;
+pub const TIOCMBIS: ::c_int = 0x5416;
+pub const TIOCMBIC: ::c_int = 0x5417;
+pub const TIOCMSET: ::c_int = 0x5418;
+pub const FIONREAD: ::c_int = 0x541B;
+pub const TIOCCONS: ::c_int = 0x541D;
 
 pub const SYS_gettid: ::c_long = 224;
 pub const SYS_perf_event_open: ::c_long = 336;

src/unix/notbsd/linux/musl/b64/mod.rs

@@ -294,36 +294,36 @@ pub const IEXTEN: ::tcflag_t = 0x00008000;
 pub const TOSTOP: ::tcflag_t = 0x00000100;
 pub const FLUSHO: ::tcflag_t = 0x00001000;
 
-pub const TCGETS: ::c_ulong = 0x5401;
-pub const TCSETS: ::c_ulong = 0x5402;
-pub const TCSETSW: ::c_ulong = 0x5403;
-pub const TCSETSF: ::c_ulong = 0x5404;
-pub const TCGETA: ::c_ulong = 0x5405;
-pub const TCSETA: ::c_ulong = 0x5406;
-pub const TCSETAW: ::c_ulong = 0x5407;
-pub const TCSETAF: ::c_ulong = 0x5408;
-pub const TCSBRK: ::c_ulong = 0x5409;
-pub const TCXONC: ::c_ulong = 0x540A;
-pub const TCFLSH: ::c_ulong = 0x540B;
-pub const TIOCGSOFTCAR: ::c_ulong = 0x5419;
-pub const TIOCSSOFTCAR: ::c_ulong = 0x541A;
-pub const TIOCLINUX: ::c_ulong = 0x541C;
-pub const TIOCGSERIAL: ::c_ulong = 0x541E;
-pub const TIOCEXCL: ::c_ulong = 0x540C;
-pub const TIOCNXCL: ::c_ulong = 0x540D;
-pub const TIOCSCTTY: ::c_ulong = 0x540E;
-pub const TIOCGPGRP: ::c_ulong = 0x540F;
-pub const TIOCSPGRP: ::c_ulong = 0x5410;
-pub const TIOCOUTQ: ::c_ulong = 0x5411;
-pub const TIOCSTI: ::c_ulong = 0x5412;
-pub const TIOCGWINSZ: ::c_ulong = 0x5413;
-pub const TIOCSWINSZ: ::c_ulong = 0x5414;
-pub const TIOCMGET: ::c_ulong = 0x5415;
-pub const TIOCMBIS: ::c_ulong = 0x5416;
-pub const TIOCMBIC: ::c_ulong = 0x5417;
-pub const TIOCMSET: ::c_ulong = 0x5418;
-pub const FIONREAD: ::c_ulong = 0x541B;
-pub const TIOCCONS: ::c_ulong = 0x541D;
+pub const TCGETS: ::c_int = 0x5401;
+pub const TCSETS: ::c_int = 0x5402;
+pub const TCSETSW: ::c_int = 0x5403;
+pub const TCSETSF: ::c_int = 0x5404;
+pub const TCGETA: ::c_int = 0x5405;
+pub const TCSETA: ::c_int = 0x5406;
+pub const TCSETAW: ::c_int = 0x5407;
+pub const TCSETAF: ::c_int = 0x5408;
+pub const TCSBRK: ::c_int = 0x5409;
+pub const TCXONC: ::c_int = 0x540A;
+pub const TCFLSH: ::c_int = 0x540B;
+pub const TIOCGSOFTCAR: ::c_int = 0x5419;
+pub const TIOCSSOFTCAR: ::c_int = 0x541A;
+pub const TIOCLINUX: ::c_int = 0x541C;
+pub const TIOCGSERIAL: ::c_int = 0x541E;
+pub const TIOCEXCL: ::c_int = 0x540C;
+pub const TIOCNXCL: ::c_int = 0x540D;
+pub const TIOCSCTTY: ::c_int = 0x540E;
+pub const TIOCGPGRP: ::c_int = 0x540F;
+pub const TIOCSPGRP: ::c_int = 0x5410;
+pub const TIOCOUTQ: ::c_int = 0x5411;
+pub const TIOCSTI: ::c_int = 0x5412;
+pub const TIOCGWINSZ: ::c_int = 0x5413;
+pub const TIOCSWINSZ: ::c_int = 0x5414;
+pub const TIOCMGET: ::c_int = 0x5415;
+pub const TIOCMBIS: ::c_int = 0x5416;
+pub const TIOCMBIC: ::c_int = 0x5417;
+pub const TIOCMSET: ::c_int = 0x5418;
+pub const FIONREAD: ::c_int = 0x541B;
+pub const TIOCCONS: ::c_int = 0x541D;
 
 cfg_if! {
     if #[cfg(target_arch = "aarch64")] {

src/unix/notbsd/linux/musl/mod.rs

@@ -143,7 +143,7 @@ pub const TCSANOW: ::c_int = 0;
 pub const TCSADRAIN: ::c_int = 1;
 pub const TCSAFLUSH: ::c_int = 2;
 
-pub const TIOCINQ: ::c_ulong = ::FIONREAD;
+pub const TIOCINQ: ::c_int = ::FIONREAD;
 
 pub const RTLD_GLOBAL: ::c_int = 0x100;
 pub const RTLD_NOLOAD: ::c_int = 0x4;