Merge ref 'df8102fe5f24:/library/compiler-builtins' from https://github.com/rust-lang/rust

Pull recent changes from rust-lang/rust via Josh.

Upstream ref: df8102fe5f24f28a918660b0cd918d7331c3896e
Filtered ref: 3c30d8c

Author: tgross35

compiler-builtins/LICENSE.txt

@@ -2,6 +2,7 @@
 #[allow(dead_code)]
 #[allow(unused_imports)]
 #[allow(clippy::all)]
+#[path = "../../../libm/src/math/mod.rs"]
 pub(crate) mod libm_math;
 
 macro_rules! libm_intrinsics {