Update the libc submodule

Brings in a few fixes for wasm/asmjs

Author: alexcrichton

src/liblibc

@@ -14,8 +14,7 @@
 
 use fmt;
 
-#[cfg(any(target_os = "emscripten",
-          all(target_os = "linux", any(target_arch = "aarch64",
+#[cfg(any(all(target_os = "linux", any(target_arch = "aarch64",
                                        target_arch = "arm",
                                        target_arch = "powerpc",
                                        target_arch = "powerpc64",
@@ -24,8 +23,7 @@ use fmt;
                                          target_arch = "arm")),
           all(target_os = "fuchsia", target_arch = "aarch64")))]
 #[stable(feature = "raw_os", since = "1.1.0")] pub type c_char = u8;
-#[cfg(not(any(target_os = "emscripten",
-              all(target_os = "linux", any(target_arch = "aarch64",
+#[cfg(not(any(all(target_os = "linux", any(target_arch = "aarch64",
                                            target_arch = "arm",
                                            target_arch = "powerpc",
                                            target_arch = "powerpc64",

src/libstd/os/raw.rs

@@ -71,13 +71,21 @@ impl FileDesc {
         #[cfg(target_os = "android")]
         use super::android::cvt_pread64;
 
-        #[cfg(not(target_os = "android"))]
+        #[cfg(target_os = "emscripten")]
         unsafe fn cvt_pread64(fd: c_int, buf: *mut c_void, count: usize, offset: i64)
             -> io::Result<isize>
         {
-            #[cfg(any(target_os = "linux", target_os = "emscripten"))]
             use libc::pread64;
-            #[cfg(not(any(target_os = "linux", target_os = "emscripten")))]
+            cvt(pread64(fd, buf, count, offset as i32))
+        }
+
+        #[cfg(not(any(target_os = "android", target_os = "emscripten")))]
+        unsafe fn cvt_pread64(fd: c_int, buf: *mut c_void, count: usize, offset: i64)
+            -> io::Result<isize>
+        {
+            #[cfg(target_os = "linux")]
+            use libc::pread64;
+            #[cfg(not(target_os = "linux"))]
             use libc::pread as pread64;
             cvt(pread64(fd, buf, count, offset))
         }
@@ -104,13 +112,21 @@ impl FileDesc {
         #[cfg(target_os = "android")]
         use super::android::cvt_pwrite64;
 
-        #[cfg(not(target_os = "android"))]
+        #[cfg(target_os = "emscripten")]
+        unsafe fn cvt_pwrite64(fd: c_int, buf: *const c_void, count: usize, offset: i64)
+            -> io::Result<isize>
+        {
+            use libc::pwrite64;
+            cvt(pwrite64(fd, buf, count, offset as i32))
+        }
+
+        #[cfg(not(any(target_os = "android", target_os = "emscripten")))]
         unsafe fn cvt_pwrite64(fd: c_int, buf: *const c_void, count: usize, offset: i64)
             -> io::Result<isize>
         {
-            #[cfg(any(target_os = "linux", target_os = "emscripten"))]
+            #[cfg(target_os = "linux")]
             use libc::pwrite64;
-            #[cfg(not(any(target_os = "linux", target_os = "emscripten")))]
+            #[cfg(not(target_os = "linux"))]
             use libc::pwrite as pwrite64;
             cvt(pwrite64(fd, buf, count, offset))
         }

src/libstd/sys/unix/fd.rs

@@ -514,6 +514,8 @@ impl File {
             SeekFrom::End(off) => (libc::SEEK_END, off),
             SeekFrom::Current(off) => (libc::SEEK_CUR, off),
         };
+        #[cfg(target_os = "emscripten")]
+        let pos = pos as i32;
         let n = cvt(unsafe { lseek64(self.0.raw(), pos, whence) })?;
         Ok(n as u64)
     }

src/libstd/sys/unix/fs.rs

@@ -10,7 +10,6 @@
 
 use io::{self, Error, ErrorKind};
 use libc::{self, c_int, gid_t, pid_t, uid_t};
-use mem;
 use ptr;
 
 use sys::cvt;
@@ -184,7 +183,9 @@ impl Command {
         }
 
         // NaCl has no signal support.
-        if cfg!(not(any(target_os = "nacl", target_os = "emscripten"))) {
+        #[cfg(not(any(target_os = "nacl", target_os = "emscripten")))]
+        {
+            use mem;
             // Reset signal handling so the child process starts in a
             // standardized state. libstd ignores SIGPIPE, and signal-handling
             // libraries often set a mask. Child processes inherit ignored