Auto merge of #29546 - alexcrichton:new-libc, r=brson

This commit replaces the in-tree liblibc with the [external clone](https://github.com/rust-lang-nursery/libc) which has no evolved beyond the in-tree version in light of its [recent redesign](https://github.com/rust-lang/rfcs/pull/1291).

The primary changes here are:

* `src/liblibc/lib.rs` was deleted
* `src/liblibc` is now a submodule pointing at the external repository
* `src/libstd/sys/unix/{c.rs,sync.rs}` were both deleted having all bindings folded into the external liblibc.
* Many ad-hoc `extern` blocks in the standard library were removed in favor of bindings now being in the external liblibc.
* Many functions/types were added to `src/libstd/sys/windows/c.rs`, and the scattered definitions throughout the standard library were consolidated here.

At the API level this commit is **not a breaking change**, although it is only very lightly tested on the *BSD variants and is probably going to break almost all of their builds! Follow-up commits to liblibc should in theory be all that's necessary to get the build working on the *BSDs again.

src/test/run-pass/issue-13259-windows-tcb-trash.rs

@@ -14,8 +14,9 @@ extern crate libc;
 
 #[cfg(windows)]
 mod imp {
-    use libc::{c_void, LPVOID, DWORD};
-    use libc::types::os::arch::extra::LPWSTR;
+    type LPVOID = *mut u8;
+    type DWORD = u32;
+    type LPWSTR = *mut u16;
 
     extern "system" {
         fn FormatMessageW(flags: DWORD,
@@ -24,15 +25,15 @@ mod imp {
                           langId: DWORD,
                           buf: LPWSTR,
                           nsize: DWORD,
-                          args: *const c_void)
+                          args: *const u8)
                           -> DWORD;
     }
 
     pub fn test() {
         let mut buf: [u16; 50] = [0; 50];
         let ret = unsafe {
-            FormatMessageW(0x1000, 0 as *mut c_void, 1, 0x400,
-                           buf.as_mut_ptr(), buf.len() as u32, 0 as *const c_void)
+            FormatMessageW(0x1000, 0 as *mut _, 1, 0x400,
+                           buf.as_mut_ptr(), buf.len() as u32, 0 as *const _)
         };
         // On some 32-bit Windowses (Win7-8 at least) this will panic with segmented
         // stacks taking control of pvArbitrary

src/test/run-pass/rfc-1014-2.rs

@@ -11,15 +11,19 @@
 
 extern crate libc;
 
+type DWORD = u32;
+type HANDLE = *mut u8;
+type BOOL = i32;
+
 #[cfg(windows)]
 extern "system" {
-    fn SetStdHandle(nStdHandle: libc::DWORD, nHandle: libc::HANDLE) -> libc::BOOL;
+    fn SetStdHandle(nStdHandle: DWORD, nHandle: HANDLE) -> BOOL;
 }
 
 #[cfg(windows)]
 fn close_stdout() {
-    const STD_OUTPUT_HANDLE: libc::DWORD = -11i32 as libc::DWORD;
-    unsafe { SetStdHandle(STD_OUTPUT_HANDLE, 0 as libc::HANDLE); }
+    const STD_OUTPUT_HANDLE: DWORD = -11i32 as DWORD;
+    unsafe { SetStdHandle(STD_OUTPUT_HANDLE, 0 as HANDLE); }
 }
 
 #[cfg(windows)]

src/test/run-pass/rfc-1014.rs

@@ -11,20 +11,24 @@
 
 extern crate libc;
 
+type DWORD = u32;
+type HANDLE = *mut u8;
+
 #[cfg(windows)]
 extern "system" {
-    pub fn GetStdHandle(which: libc::DWORD) -> libc::HANDLE;
+    fn GetStdHandle(which: DWORD) -> HANDLE;
+    fn CloseHandle(handle: HANDLE) -> i32;
 }
 
 #[cfg(windows)]
 fn close_stdout() {
-    const STD_OUTPUT_HANDLE: libc::DWORD = -11i32 as libc::DWORD;
-    unsafe { libc::CloseHandle(GetStdHandle(STD_OUTPUT_HANDLE)); }
+    const STD_OUTPUT_HANDLE: DWORD = -11i32 as DWORD;
+    unsafe { CloseHandle(GetStdHandle(STD_OUTPUT_HANDLE)); }
 }
 
 #[cfg(not(windows))]
 fn close_stdout() {
-    unsafe { libc::close(libc::STDOUT_FILENO); }
+    unsafe { libc::close(1); }
 }
 
 fn main() {

src/test/run-pass/wait-forked-but-failed-child.rs

@@ -15,8 +15,6 @@ extern crate libc;
 
 use std::process::Command;
 
-use libc::funcs::posix88::unistd;
-
 // The output from "ps -A -o pid,ppid,args" should look like this:
 //   PID  PPID COMMAND
 //     1     0 /sbin/init
@@ -34,7 +32,7 @@ use libc::funcs::posix88::unistd;
 
 #[cfg(unix)]
 fn find_zombies() {
-    let my_pid = unsafe { unistd::getpid() };
+    let my_pid = unsafe { libc::getpid() };
 
     // http://pubs.opengroup.org/onlinepubs/9699919799/utilities/ps.html
     let ps_cmd_output = Command::new("ps").args(&["-A", "-o", "pid,ppid,args"]).output().unwrap();