[libc] Temporary math macros fix

Downstream's having some issues due to math-macros.h issues. These will
be fixed properly soon.

Author: michaelrj-google

libc/include/llvm-libc-macros/math-macros.h

@@ -9,6 +9,9 @@
 #ifndef LLVM_LIBC_MACROS_MATH_MACROS_H
 #define LLVM_LIBC_MACROS_MATH_MACROS_H
 
+// TODO: Remove this. This is a temporary fix for a downstream problem.
+#ifdef LLVM_LIBC_FULLBUILD
+
 #include "limits-macros.h"
 
 #define FP_NAN 0
@@ -79,4 +82,10 @@ template <typename T> inline constexpr bool isnan(T x) {
 
 #endif
 
+#else
+
+#include <math.h>
+
+#endif // LLVM_LIBC_FULLBUILD
+
 #endif // LLVM_LIBC_MACROS_MATH_MACROS_H

utils/bazel/llvm-project-overlay/libc/BUILD.bazel

@@ -68,7 +68,6 @@ libc_support_library(
     name = "llvm_libc_macros_math_macros",
     hdrs = ["include/llvm-libc-macros/math-macros.h"],
     deps = [":llvm_libc_macros_limits_macros"],
-    defines = ["__FP_LOGBNAN_MIN"],
 )
 
 libc_support_library(
@@ -1000,8 +999,8 @@ libc_support_library(
 
 libc_support_library(
     name = "__support_osutil_quick_exit",
-    hdrs = ["src/__support/OSUtil/quick_exit.h"],
     srcs = ["src/__support/OSUtil/linux/quick_exit.cpp"],
+    hdrs = ["src/__support/OSUtil/quick_exit.h"],
     deps = [
         ":__support_osutil_syscall",
     ],