Fix breaking change on linux due to inclusion of Windows header.

include/ReWindow/types/Window.h

@@ -9,8 +9,11 @@
 #include <ReWindow/types/MouseButton.h>
 #include <ReWindow/types/WindowEvents.h>
 #include <queue>
-#include <Windows.h>
 
+// TODO: Hide this eventually if possible.
+#ifdef WIN32
+#include <Windows.h>
+#endif
 
 namespace ReWindow {
     struct KeyboardState { std::map<Key, bool> PressedKeys; };