mesa: Like EXT_texture_compression_dxt1, advertise ANGLE_texture_compression_dxt in all APIs

This is technically outside the ANGLE spec, but it seems unlikely to
cause any harm.

v2: Simplify the extension checks by assuming the ANGLE extension will
always be enabled by any driver that enables the EXT.  Suggested by
Eric Anholt.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Acked-by: Lee Salzman <lsalzman@gmail.com>
3 files changed