If --enable-cairo is provided, ensure that we actually get CAIRO support. If we don't, then abort and let a human figure it out.
If --enable-cairo is provided, ensure that we actually get CAIRO support.
If we don't, then abort and let a human figure it out.

(inspired from r3546)



git-svn-id: 14be032f8f42541b1a281b51ae8ea69814daf20e@3557 4b44e086-7f34-40ce-a3bd-00e031736276

BlueBrain/hwloc,BlueBrain/hwloc,BlueBrain/hwloc,BlueBrain/hwloc