Make it compatible for Android.

* Fixed an unused_import error in `termios.rs` for Android.
* Fixed undefined references to `preadv` and `pwritev` for Android -
  At least they don't exist from API level 3 to 21.
* Fixed the uid > 0 and gid > 0 checks in `stat`'s tests - Running the
  tests by root is possible, especially when running on a rooted Android
  device.

Those changes made rust-nix buildable (again) on Android. All the tests
passed as well.

1 files changed, 24 insertions, 18 deletions

diff --git a/src/sys/termios.rs b/src/sys/termios.rs
index 4050e7d5..a9fd41ec 100644
--- a/src/sys/termios.rs
+++ b/src/sys/termios.rs
@@ -10,29 +10,35 @@ pub use self::ffi::consts::FlushArg::*;
 pub use self::ffi::consts::FlowArg::*;
 
 mod ffi {
-    use libc::c_int;
-
     pub use self::consts::*;
 
-    // `Termios` contains bitflags which are not considered
-    // `foreign-function-safe` by the compiler.
-    #[allow(improper_ctypes)]
     #[cfg(any(target_os = "macos", target_os = "freebsd", target_os = "openbsd", target_os = "linux"))]
-    extern {
-        pub fn cfgetispeed(termios: *const Termios) -> speed_t;
-        pub fn cfgetospeed(termios: *const Termios) -> speed_t;
-        pub fn cfsetispeed(termios: *mut Termios, speed: speed_t) -> c_int;
-        pub fn cfsetospeed(termios: *mut Termios, speed: speed_t) -> c_int;
-        pub fn tcgetattr(fd: c_int, termios: *mut Termios) -> c_int;
-        pub fn tcsetattr(fd: c_int,
-                         optional_actions: c_int,
-                         termios: *const Termios) -> c_int;
-        pub fn tcdrain(fd: c_int) -> c_int;
-        pub fn tcflow(fd: c_int, action: c_int) -> c_int;
-        pub fn tcflush(fd: c_int, action: c_int) -> c_int;
-        pub fn tcsendbreak(fd: c_int, duration: c_int) -> c_int;
+    mod non_android {
+        use super::consts::*;
+        use libc::c_int;
+
+        // `Termios` contains bitflags which are not considered
+        // `foreign-function-safe` by the compiler.
+        #[allow(improper_ctypes)]
+        extern {
+            pub fn cfgetispeed(termios: *const Termios) -> speed_t;
+            pub fn cfgetospeed(termios: *const Termios) -> speed_t;
+            pub fn cfsetispeed(termios: *mut Termios, speed: speed_t) -> c_int;
+            pub fn cfsetospeed(termios: *mut Termios, speed: speed_t) -> c_int;
+            pub fn tcgetattr(fd: c_int, termios: *mut Termios) -> c_int;
+            pub fn tcsetattr(fd: c_int,
+                             optional_actions: c_int,
+                             termios: *const Termios) -> c_int;
+            pub fn tcdrain(fd: c_int) -> c_int;
+            pub fn tcflow(fd: c_int, action: c_int) -> c_int;
+            pub fn tcflush(fd: c_int, action: c_int) -> c_int;
+            pub fn tcsendbreak(fd: c_int, duration: c_int) -> c_int;
+        }
     }
 
+    #[cfg(any(target_os = "macos", target_os = "freebsd", target_os = "openbsd", target_os = "linux"))]
+    pub use self::non_android::*;
+
     // On Android before 5.0, Bionic directly inline these to ioctl() calls.
     #[inline]
     #[cfg(all(target_os = "android", not(target_arch = "mips")))]