Didn't need to add SDL_windows.h include, that was already included
diff --git a/src/thread/windows/SDL_systhread.c b/src/thread/windows/SDL_systhread.c
index 2824969..3e1375b 100644
--- a/src/thread/windows/SDL_systhread.c
+++ b/src/thread/windows/SDL_systhread.c
@@ -29,7 +29,6 @@
 #include "../SDL_thread_c.h"
 #include "../SDL_systhread.h"
 #include "SDL_systhread_c.h"
-#include "../../core/windows/SDL_windows.h"
 
 #ifndef SDL_PASSED_BEGINTHREAD_ENDTHREAD
 /* We'll use the C library from this DLL */