diff --git a/src/platform/platform.h b/src/platform/platform.h
index ad73ee361d..dccafe8e92 100644
--- a/src/platform/platform.h
+++ b/src/platform/platform.h
@@ -20,7 +20,9 @@
 #include "../common.h"
 
 #ifdef __WINDOWS__
-#define HAVE_MATH_H
+	#ifndef HAVE_MATH_H
+		#define HAVE_MATH_H
+	#endif
 #endif // __WINDOWS__
 
 #include <SDL.h>
diff --git a/src/rct2.h b/src/rct2.h
index 6b47f4f2ae..ac9c01245e 100644
--- a/src/rct2.h
+++ b/src/rct2.h
@@ -18,6 +18,7 @@
 #define _RCT2_H_
 
 #include <SDL_platform.h>
+#include <SDL_config.h>
 
 #ifndef _USE_MATH_DEFINES
 	#define _USE_MATH_DEFINES