Add protection from min/max macros

llvm-svn: 145407
diff --git a/libcxx/include/random b/libcxx/include/random
index c5c33c0..e14425d 100644
--- a/libcxx/include/random
+++ b/libcxx/include/random
@@ -1646,6 +1646,8 @@
 #include <ostream>
 #include <cmath>
 
+#include <__undef_min_max>
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif