This module can be used to retrieve path of a directory with all wayland-protocols'
protocols, like xdg-shell, and so on.
Example usage
find_package(WaylandProtocols REQUIRED) ecm_add_wayland_client_protocol(CLIENT_LIB_SRCS PROTOCOL ${WaylandProtocols_DATADIR}/stable/xdg-shell/xdg-shell.xml BASENAME xdg-shell )