(svn r19807) -Codechange: instead of having an unnamed enum and passing it as an int, name the enum and pass that

src/main_gui.cpp

@@ -128,7 +128,7 @@ void ShowNetworkGiveMoneyWindow(CompanyID company)
 
 /* Zooms a viewport in a window in or out
  * No button handling or what so ever */
-bool DoZoomInOutWindow(int how, Window *w)
+bool DoZoomInOutWindow(ZoomStateChange how, Window *w)
 {
 	ViewPort *vp;
 
@@ -136,6 +136,7 @@ bool DoZoomInOutWindow(int how, Window *w)
 	vp = w->viewport;
 
 	switch (how) {
+		case ZOOM_NONE: NOT_REACHED();
 		case ZOOM_IN:
 			if (vp->zoom == ZOOM_LVL_MIN) return false;
 			vp->zoom = (ZoomLevel)((int)vp->zoom - 1);