Ignore unused_unsafe lint in libm/src/math/arch/x86/detect.rs

Author: taiki-e

libm/src/math/arch/x86/detect.rs

@@ -39,6 +39,8 @@ pub fn get_cpu_features() -> Flags {
 /// Implementation is taken from [std-detect][std-detect].
 ///
 /// [std-detect]: https://github.com/rust-lang/stdarch/blob/690b3a6334d482874163bd6fcef408e0518febe9/crates/std_detect/src/detect/os/x86.rs#L142
+// FIXME(msrv): Remove unsafe block around __cpuid once https://github.com/rust-lang/stdarch/pull/1935 is available in MSRV.
+#[allow(unused_unsafe)]
 fn load_x86_features() -> Flags {
     let mut value = Flags::empty();