Merge pull request #127 from nivkner/term_size

use `TIOCGWINSZ` directly from `libc`

src/sys/unix/size.rs

 use std::{io, mem};
 
 use super::cvt;
-use super::libc::{c_ushort, ioctl, STDOUT_FILENO};
+use super::libc::{c_ushort, ioctl, STDOUT_FILENO, TIOCGWINSZ};
 
 #[repr(C)]
 struct TermSize {
@@ -10,39 +10,11 @@ struct TermSize {
     _x: c_ushort,
     _y: c_ushort,
 }
-
-#[cfg(target_os = "linux")]
-pub const TIOCGWINSZ: usize = 0x00005413;
-
-#[cfg(not(target_os = "linux"))]
-pub const TIOCGWINSZ: usize = 0x40087468;
-
-// Since attributes on non-item statements is not stable yet, we use a function.
-#[cfg(not(target_os = "android"))]
-#[cfg(not(target_os = "redox"))]
-#[cfg(target_pointer_width = "64")]
-#[cfg(not(target_env = "musl"))]
-fn tiocgwinsz() -> u64 {
-    TIOCGWINSZ as u64
-}
-#[cfg(not(target_os = "android"))]
-#[cfg(not(target_os = "redox"))]
-#[cfg(target_pointer_width = "32")]
-#[cfg(not(target_env = "musl"))]
-fn tiocgwinsz() -> u32 {
-    TIOCGWINSZ as u32
-}
-
-#[cfg(any(target_env = "musl", target_os = "android"))]
-fn tiocgwinsz() -> i32 {
-    TIOCGWINSZ as i32
-}
-
 /// Get the size of the terminal.
 pub fn terminal_size() -> io::Result<(u16, u16)> {
     unsafe {
         let mut size: TermSize = mem::zeroed();
-        cvt(ioctl(STDOUT_FILENO, tiocgwinsz(), &mut size as *mut _))?;
+        cvt(ioctl(STDOUT_FILENO, TIOCGWINSZ, &mut size as *mut _))?;
         Ok((size.col as u16, size.row as u16))
     }
 }