build: deduplicate sources
Shorten the needed sources from
calls_sources, calls_enum_sources, calls_resources,
wl_proto_sources, wayland_sources,
to
calls_sources
so adding new things such as generated dbus sources doesn't have to happen in four locations but just one.
There was heaps of duplication and each new test broke things again due to incomplete sources. Consolidate this. I would have postponed but this makes rebases simpler.
Edited by Guido Gunther