Set a default XKB keymap on the headless keyboard device in
wl_display_open() so the keyboard has a keycode↔keysym mapping
available from startup.
Implement wl_keysym_to_keycode() by scanning the XKB keymap for the
first keycode that produces the given keysym; XKB keycodes equal
evdev+8 == X11 keycodes, so wKeyBindings are directly compatible.
Implement wl_keysym_from_keycode() as the reverse lookup.
Call wSetModifierMasks(Mod1Mask, Mod1Mask, Mod4Mask, 0) from
wl_screen_create_internals() so AltMask/MetaMask/SuperMask are
non-zero in Wayland mode, making modifier parsing in wXModifierFromKey
produce correct values.
Add wSetModifierMasks() to xmodifier.c/h as the non-X11 entry point.
Replace the four XKeysymToKeycode(dpy, ksym) call sites in
defaults.c, rootmenu.c, and usermenu.c with
wm_backend->keysym_to_keycode() so they work when dpy==NULL.
Smoke test: check for "XKB keymap set on headless keyboard" log line.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
b1e4a99c5d