Factorize boolean user prompting.

Introduce a new `status_ask_bool()` function, and use it where
applicable.

This greatly reduces code duplication, and will allow handling special
events (resize, user escape) much more uniformely.

Signed-off-by: Baptiste Jonglez <baptiste--git@jonglez.org>
Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

src/calcurse.c

@@ -546,10 +546,8 @@ main (int argc, char **argv)
 
           if (conf.confirm_quit)
             {
-              status_mesg_yesno (_("Do you really want to quit ?"));
-              key = wgetch (win[STA].p);
-              if (key == 'y')
-                exit_calcurse (EXIT_SUCCESS);
+              if (status_ask_bool (_("Do you really want to quit ?")) == 1)
+                  exit_calcurse (EXIT_SUCCESS);
               else
                 {
                   wins_erase_status_bar ();