Add a shim from llvm_asm! to asm! for stdarch

Author: cuviper

src/libcore/internal_macros.rs

@@ -117,3 +117,8 @@ macro_rules! impl_fn_for_zst {
         )+
     }
 }
+
+macro_rules! llvm_asm {
+    // Redirect to asm! for stdarch in stable 1.43
+    ($($arg:tt)*) => { $crate::asm!($($arg)*) }
+}