typo...

src/mainwin.h

@@ -69,7 +69,7 @@ class MainWin : public SkylivexWin
       WebWin* yt;             // a pointer to the special (singleton) Youtube window (if exists)
       bool yt_is_open;        // a boolean to indicate if the Youtube window is open
 #if defined(Q_OS_MAC)
-      bool yt_if_fallback;
+      bool yt_is_fallback;
 #endif
       void handle_corestarted(SKMessage &msg);
       void handle_connected(SKMessage &msg);