compatibility with wxWdigets 2.9+: use HandleWindowEvent instead of...

compatibility with wxWdigets 2.9+: use HandleWindowEvent instead of ProcessEvent, but this function doesn't exist in wx2.8. So, #define the former as the latter for backwards compatibility.

src/util/prec.hpp

@@ -60,6 +60,10 @@ typedef wxOutputStream OutputStream;
 #if wxVERSION_NUMBER < 2805
 	#define wxBORDER_THEME wxSUNKEN_BORDER
 #endif
+#if wxVERSION_NUMBER < 2900
+	// wx >= 2.9 requires the use of HandleWindowEvent on windows, instead of ProcessEvent
+	#define HandleWindowEvent ProcessEvent
+#endif
 
 // ----------------------------------------------------------------------------- : Other aliasses