Initial checkin for debug mode (version 2)

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@139711 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/__config b/include/__config
index fffcfaa..2751619 100644
--- a/include/__config
+++ b/include/__config
@@ -309,4 +309,10 @@
 #define _LIBCPP_WCTYPE_IS_MASK
 #endif
 
+#ifdef _LIBCPP_DEBUG2
+#   include <__debug>
+#else
+#   define _LIBCPP_ASSERT(x, m) ((void)0)
+#endif
+
 #endif  // _LIBCPP_CONFIG