Add missing wayland-server CFLAGS for protocol/*-protocol.o
xserver: Handle stale lockfiles
xkb: Drop swc_ prefix for non-public structures/functions
xkb: Remove unused function xkb_update_key_indices
Reset keyboard state on session deactivation

This prevents an inconsistent state of the keyboard when the VT is
switched away with keys held down.
keyboard: Ignore unpaired key release events

If we see a release for a key we didn't know was pressed, it is because
the key was pressed when we opened the device. These are safe to ignore
because our internal state of the keyboard considered them unpressed.

This fixes a crash when the swc VT is switched to from a text VT, due to
accidently handling a key release like a key press.
Style