avoid ctrl_nhwindow-related impossible

Remove the impossible(), so that new functionality can be added
incrementally without requiring every window-port to be visited up front.

win/Qt/qt_bind.cpp

@@ -514,11 +514,13 @@ win_request_info *NetHackQtBind::qt_ctrl_nhwindow(
         return (win_request_info *) 0;
 
     switch(request) {
+    case set_mode:
+    case request_settings:
+        break;
     case set_menu_promptstyle:
         /* = wri->fromcore.menu_promptstyle; */
         break;
     default:
-        impossible("invalid request to ctrl_nhwindow: %d", request);
         break;
     }
     return wri;

win/X11/winX.c

@@ -1313,11 +1313,13 @@ X11_ctrl_nhwindow(
         return (win_request_info *) 0;
 
     switch(request) {
+    case set_mode:
+    case request_settings:
+        break;
     case set_menu_promptstyle:
         X11_menu_promptstyle = wri->fromcore.menu_promptstyle;
         break;
     default:
-        impossible("invalid request to ctrl_nhwindow: %d", request);
         break;
     }
     return wri;

win/curses/cursmain.c

@@ -809,11 +809,9 @@ curses_ctrl_nhwindow(
         return (win_request_info *) 0;
 
     switch (request) {
-#if 0
     case set_mode:
     case request_settings:
         break;
-#endif
     case set_menu_promptstyle:
 	curses_menu_promptstyle.color = wri->fromcore.menu_promptstyle.color;
         if (curses_menu_promptstyle.color == NO_COLOR)
@@ -822,7 +820,6 @@ curses_ctrl_nhwindow(
 	curses_menu_promptstyle.attr = curses_convert_attr(attr);;
         break;
     default:
-        impossible("invalid request to ctrl_nhwindow: %d", request);
         break;
     }
     return wri;

win/tty/wintty.c

@@ -2823,9 +2823,9 @@ tty_ctrl_nhwindow(winid window UNUSED, int request, win_request_info *wri)
         return (win_request_info *) 0;
 
     switch (request) {
-#if defined(TTY_PERM_INVENT)
     case set_mode:
     case request_settings:
+#if defined(TTY_PERM_INVENT)
         ttyinvmode = wri->fromcore.invmode;
         if (request == set_mode)
             break;
@@ -2850,13 +2850,12 @@ tty_ctrl_nhwindow(winid window UNUSED, int request, win_request_info *wri)
             maxslot = (maxrow - 2) * (!inuse_only ? 2 : 1);
             wri->tocore.maxslot = maxslot;
         }
-        break;
 #endif  /* TTY_PERM_INVENT */
+        break;
     case set_menu_promptstyle:
         tty_menu_promptstyle = wri->fromcore.menu_promptstyle;
         break;
     default:
-        impossible("invalid request to tty_ctrl_nhwindow: %d", request);
         break;
     }
     return wri;

win/win32/mswproc.c

@@ -1260,11 +1260,13 @@ mswin_ctrl_nhwindow(
         return (win_request_info *) 0;
 
     switch(request) {
+    case set_mode:
+    case request_settings:
+        break;
     case set_menu_promptstyle:
         mswin_menu_promptstyle = wri->fromcore.menu_promptstyle;
         break;
     default:
-        impossible("invalid request to ctrl_nhwindow: %d", request);
         break;
     }
     return wri;