D-Bus display does fails to build if libgdm is not detected

Attempting to build qemu from git HEAD today with DBus-Display enabled fails;

../ui/dbus-listener.c: In function ‘dbus_scanout_texture’:
../ui/dbus-listener.c:131:17: error: implicit declaration of function ‘egl_get_fd_for_texture’ [-Werror=implicit-function-declaration]

This function is defined in egl-helpers.h but it is only exposed if CONFIG_GDM is defined - on my system I did not have libgdm-dev installed. This suggests that the meson rules need to add a dependency on GDM to DBus-Display.