Merge commit '9754257a8b8b' from apple/main into swift/next

git apple-llvm automerger · git apple-llvm automerger · commit 57f5088e49be · 2020-12-14T08:51:54.000-08:00
diff --git a/libc/utils/FPUtil/DummyFEnv.h b/libc/utils/FPUtil/DummyFEnv.h
@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_UTILS_FPUTIL_DUMMY_FENV_H
 #define LLVM_LIBC_UTILS_FPUTIL_DUMMY_FENV_H
 
+#include <fenv.h>
 #include <math.h>
 
 namespace __llvm_libc {
