Index: compiler-rt/trunk/lib/sanitizer_common/sanitizer_win_defs.h
===================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_win_defs.h
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_win_defs.h
@@ -16,11 +16,13 @@
 #include "sanitizer_platform.h"
 #if SANITIZER_WINDOWS
 
+#ifndef WINAPI
 #ifdef _M_IX86
 #define WINAPI __stdcall
 #else
 #define WINAPI
 #endif
+#endif
 
 #if defined(_WIN64)
 #define WIN_SYM_PREFIX