Ian Romanick authored Jul 04, 2012 and Keith Packard committed Jul 05, 2012

Most of the infrastructure was already in place.  This just adds:

    * Validate values specified with the GLX_CONTEXT_PROFILE_MASK_ARB
      attribute.

    * Select a DRI2 "api" based on the setting of
      GLX_CONTEXT_PROFILE_MASK_ARB.

    * Enable GLX_ARB_create_context_profile extension.

This change assumes that any DRI2 driver can handle (possibly by saying "no")
seeing an API setting other than __DRI_API_OPENGL.  This allows enabling this
extension any time GLX_ARB_create_context is enabled.

Also, the validation code in __glXDisp_CreateContextAttribsARB is structured
in a very verbose manner (using a switch-statement) to ease the addition of
GLX_EXT_create_context_es2_profile.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>