libepoxy: make buildable for x11-less environments / update to latest version
* Make glx part configurable by PACKAGECONFIG enabled by 'x11' distro feature
* Major upstream enhancement is using pkgconfig for egl. This should make
those egl implementations happy that require compiler extra options for their
egl headers.
Example: meta-fsl-arm/imx-gpu-viv sets -DLINUX (and others) in egl.pc. These
are mandatory for proper builds.
Signed-off-by: Andreas Müller <schnitzeltony@googlemail.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
