Added WIN_ESC mode bit to main menu (active when escape is hit).

src/sbbs3/install/sbbsinst.c

@@ -278,7 +278,7 @@ int main(int argc, char **argv)
 
 		uifc.helpbuf=	"`Synchronet Installation Settings:`\n"
 						"\nToDo: Add help.";
-		switch(uifc.list(WIN_MID|WIN_ACT,0,0,60,&main_dflt,0
+		switch(uifc.list(WIN_ESC|WIN_MID|WIN_ACT,0,0,60,&main_dflt,0
 			,"Synchronet Installation Settings",mopt)) {
 			case 0:
 				i=choose_dist((char **)distlist);