diff --git a/include/SDL_stdinc.h b/include/SDL_stdinc.h
index d5163436c..d2002ba2e 100644
--- a/include/SDL_stdinc.h
+++ b/include/SDL_stdinc.h
@@ -633,8 +633,10 @@ extern DECLSPEC int SDLCALL SDL_vsnprintf(char *text, size_t maxlen,
 #endif
 
 #ifndef HAVE_M_PI
+#ifndef M_PI
 #define M_PI    3.14159265358979323846264338327950288   /* pi */
 #endif
+#endif
 
 #ifdef HAVE_ATAN
 #define SDL_atan        atan