diff --git a/src/win32_platform.h b/src/win32_platform.h
index 63a372d7..7bfd5995 100644
--- a/src/win32_platform.h
+++ b/src/win32_platform.h
@@ -33,8 +33,13 @@
 
 
 // We don't need all the fancy stuff
-#define NOMINMAX
-#define VC_EXTRALEAN
+#ifndef NOMINMAX
+ #define NOMINMAX
+#endif
+
+#ifndef VC_EXTRALEAN
+ #define VC_EXTRALEAN
+#endif
 
 #ifndef WIN32_LEAN_AND_MEAN
  #define WIN32_LEAN_AND_MEAN