diff --git a/src/core/system.h b/src/core/system.h
index 3c83b9c5c..a08c48a8b 100644
--- a/src/core/system.h
+++ b/src/core/system.h
@@ -7,6 +7,7 @@ extern "C" {
 #endif
     
 #include <stdint.h>
+#include <stddef.h>
 #include <SDL2/SDL_platform.h>
 #include <SDL2/SDL_opengl.h>