Bug: configure does not check for gl

[Pekka Paalanen]

Hi all,

Anisse reported, that Debian splits Mesa into packages in such a way,
that we may miss gl.pc and GL/gl.h, even when the egl.pc and GLESv2
checks pass. We would need to check for gl.pc, too.

We cannot simply add 'gl' to the PKG_CHECK_MODULES(CLIENT, ... line, as
that might cause us to link both GL and GLESv2 libraries (via Cairo),
which I hear is a "recipe for pain". So we would want to conditionalise
those on the Cairo gl vs. glesv2 switch.

We might also need to fix window.c to properly choose between GL
headers and GLESv2 headers.

Since we don't have a bugzilla yet, AFAIK, this email stands as the
report. I'm not taking this one for myself yet, so patches welcome.


Thanks,
pq