Index: libcxxabi/include/__cxxabi_config.h
===================================================================
--- libcxxabi/include/__cxxabi_config.h
+++ libcxxabi/include/__cxxabi_config.h
@@ -53,7 +53,7 @@
  #endif
 #endif
 
-#if defined(_WIN32)
+#if defined(_MSC_VER)
 #define _LIBCXXABI_WEAK
 #else
 #define _LIBCXXABI_WEAK __attribute__((__weak__))