[libc] [llvm] [libc] Add proxy header for fenv.h macro constants. #87863 (PR #87896)

[via llvm-commits]

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@@ -8,7 +8,7 @@
 
 #include "FPExceptMatcher.h"
 
-#include <fenv.h>
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lntue wrote:

Don't replace the include for this file yet, it only uses `fenv_t` and does not use any of the macro constants from `fenv.h`.

https://github.com/llvm/llvm-project/pull/87896