[PATCH xf86-video-dummy] Add glamor acceleration which enables native OpenGL support

[Emil Velikov]

On 8 March 2017 at 01:04, Yu, Qiang <Qiang.Yu at amd.com> wrote:
>
>> You want to AC_MSG_ERROR if the the option is set to "yes" and it's
>> not available. Currently one silently ignores it, which is not good.
> Right, so I need to make it "auto" by default?
>
If you change the current default to "auto" that will fit the code
better. At the same time you'll still get the feature silently
disabled even if you _explicitly_ enable it.
Something like the following should do it.

check_all_dependencies(...., have_glamor=yes, have_glamor=no) //
pseudo code/function - set variable to 'yes', if deps are met, and
'no' otherwise

case "$enable_glamor,$have_glamor" in
       yes,yes | auto,yes)
               ;;
       yes,no)
               AC_MSG_ERROR([GLAMOR requested, but $dependencies not found.])
               ;;
       no,*)
               ;;
       *)
               AC_MSG_NOTICE([GLAMOR disabled because $dependencies not found.])
               enable_glamor=no
               ;;
esac

-Emil