Windows support by Ruben Van Boxem.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@142235 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/cfloat b/include/cfloat
index f0079c2..5fa5655 100644
--- a/include/cfloat
+++ b/include/cfloat
@@ -63,7 +63,9 @@
 #include <__config>
 #include <float.h>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
+#endif
 
 #ifndef FLT_EVAL_METHOD
 #define FLT_EVAL_METHOD __FLT_EVAL_METHOD__