Remove all the roadblocks we've put up to keep implicit modifiers
out. Our importing code already handles them as a signal that says
'No modifiers, please!'. Now we just hope for the best and pass
things along.
This is necessary since some drivers won't produce any explicit
modifiers.
Trying to use it is a programming error, applications should have code
that uses real modifiers.
Also add a check to the formatsbuilder so our code doesn't include the
invalid modifier by accident.
We don't really know how to deal with it, so better force applications
to figure out what to do.
This seems to be what everyone does, so we should do it, too.
Previously it was assumed that an fd of -1 would mean reusing the
previous fd with a different offset, but that seems to be uncommon.
We always have a display - the default display - so there's no need to
accept NULL.
Plus, we need a display when building the texture, so accepthing NULL
wouldn't even make sense.
Includes update to defaultvalue test.
GdkDmabuf is a struct encapsulating all the values of a dmabuf, so
nothing to see here.
GdkDmabufDownloader is a vtable for a thing that can download dmabufs.
For now only one implementation exists, so this just looks like a ton
of work for no benefit.
The only neat thing is that gdkdmabuftexture.c got a whole lot tidier.
Add an implementation of GdkDmabufTexture.
For now, this implementation is rather minimal,
since we need a roundtrip through GL to convert
most nottrivial formats.
Add a builder for a new GdkTexture subclass that
wraps dmabuf buffers on Linux. For now, this is
just an API. The implementation will follow in
subsequent commits.
