Update rust-lang/stdarch submodule

src/libstd/lib.rs

@@ -335,12 +335,6 @@ extern crate libc;
 #[allow(unused_extern_crates)]
 extern crate unwind;
 
-// Only needed for now for the `std_detect` module until that crate changes to
-// use `cfg_if::cfg_if!`
-#[macro_use]
-#[cfg(not(test))]
-extern crate cfg_if;
-
 // During testing, this crate is not actually the "real" std library, but rather
 // it links to the real std library, which was compiled from this same source
 // code. So any lang items std defines are conditionally excluded (or else they

src/libstd/tests/run-time-detect.rs

@@ -6,6 +6,7 @@
         all(target_arch = "aarch64", any(target_os = "linux", target_os = "android")),
         all(target_arch = "powerpc", target_os = "linux"),
         all(target_arch = "powerpc64", target_os = "linux"),
+        any(target_arch = "x86", target_arch = "x86_64"),
     ),
     feature(stdsimd)
 )]