Auto merge of #607 - humenda:master, r=alexcrichton

Add x86_64 module to uclibc/mod.rs

Author: bors

src/unix/uclibc/mod.rs

@@ -1759,6 +1759,9 @@ cfg_if! {
     if #[cfg(target_arch = "mips")] {
         mod mips;
         pub use self::mips::*;
+    } else if #[cfg(target_arch = "x86_64")] {
+        mod x86_64;
+        pub use self::x86_64::*;
     } else {
         pub use unsupported_target;
     }