^A/#repeat vs extended commands

Fix '#repeat' for tty; both it and ^A can repeat an extended command.

Fix both for curses; they can repeat an extended command instead of
just repeating the initial '#' to start getting an extended command.

X11 (tested), Qt (tested), and probably Windows GUI (not tested)
behave the same as before:  ^A (or #repeat) after an extended command
just repeats the # to run the dialog to get an extended command.

I hope this introduces fewer bugs than it fixes but I don't think I'd
bet on that....

win/Qt/qt_xcmd.cpp

@@ -581,7 +581,15 @@ int NetHackQtExtCmdRequestor::get()
     }
     if (result() == xcmdNone)
 	exec();
-    return result() - 1;
+
+    int ret = result() - 1;
+    if (!::g.in_doagain) {
+        if (ret >= 0)
+            savech_extcmd(::extcmdlist[ret].ef_txt, FALSE);
+        else
+            savech(0);
+    }
+    return ret;
 }
 
 // Enable only buttons that match the current prompt string