mesa: expose ARB_seamless_cubemap_per_texture when supported

All of the bits appear to already be in place to support this in the
sampler (which the original AMD version didn't allow).

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
st/omx: strcpy the string into the allocated buffer

This fixes commit a001ca98e15(st/omx: keep the name,
(name|role)_specific strings dynamically allocated) in which we
dynamically allocated the buffers for name and (name|role)_specific
yet forgot to copy the encoder strings into them.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80614
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>