glapi: Enable ES compatibility mode

glapi: Enable ES compatibility mode

Ages ago Chia-I added an ES compatibility flag to several of the various
generator scripts.  The intention was to bridge differences between ES
and desktop in Mesa builds without ES.  It doesn't appear that it has
ever been used.  Recent changes to static_dispatch status of several ES1
functions caused problems in desktop-only, non-shared-glapi builds.
Enabling the ES compatibility mode appears to fix these build problems.

This is kind of a duct tape solution to this problem.  As I mentioned in
the cover letter for the series that triggered the build problem, I
would like to make some major changes to the generator architecture and
the XML.  The whole point of the proposed architecture changes is to
better handle the differences between desktop GL and ES.  I think duct
tape is okay for now.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76869
Tested-by: Brian Paul <brianp@vmware.com>
Tested-by: Lu Hua <huax.lu@intel.com>
Cc: Vinson Lee <vlee@freedesktop.org>
Cc: Chia-I Wu <olv@lunarg.com>