Map evdev keycode KEY_KEYBOARD to XF86Keyboard

NB: XF86Keyboard is a relatively new keysym and therefore needs
recent protocol headers. Also KEY_KEYBOARD's keysym is > 255
and therefore needs a recent xkbcomp (as the new KEY_FAVORITES).

https://bugs.freedesktop.org/show_bug.cgi?id=101521



Signed-off-by: Christian Kellner <christian@kellner.me>