Fix building with latest compiler. am: b9b96960c2 am: d961497afd am: 5f60786769 am: cd3f7e1a84

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/libm/+/1907153

Change-Id: I8e4f8f1245bed280de89f29ff6e43aa70aedcdb2