[mutter/gnome-3-36] keybindings: Mask out the reserved modifiers mask

[Robert Mader <rmader src gnome org>]

commit 2cc8061f352e99767a33536b37b241e974092adb
Author: Olivier Fourdan <ofourdan redhat com>
Date:   Mon Apr 27 17:01:22 2020 +0200

    keybindings: Mask out the reserved modifiers mask
    
    When switching layouts, special modifiers bits may be be set for
    internal use by Xkb.
    
    As we now ignore a set of modifiers when processing the special
    modifiers keys, we ought to also mask out those reserved modifiers
    otherwise we would discard the [Super] key after switching layouts
    in X11.
    
    Closes: https://gitlab.gnome.org/GNOME/mutter/issues/1144
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1219
    
    (cherry picked from commit 61356caa0693f19ccb289597bbab5138319e7f3c)

 src/core/keybindings.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/core/keybindings.c b/src/core/keybindings.c
index 7f930874f..957c77a8f 100644
--- a/src/core/keybindings.c
+++ b/src/core/keybindings.c
@@ -2129,7 +2129,7 @@ process_special_modifier_key (MetaDisplay          *display,
       return TRUE;
     }
   else if (event->type == CLUTTER_KEY_PRESS &&
-           (event->modifier_state & ~(IGNORED_MODIFIERS)) == 0 &&
+           ((event->modifier_state & ~(IGNORED_MODIFIERS)) & CLUTTER_MODIFIER_MASK) == 0 &&
            resolved_key_combo_has_keycode (resolved_key_combo,
                                            event->hardware_keycode))
     {