Add options for DRI{1,2,3}
shmfence is required for DRI3
libdrm is required for any DRI{1,2,3}
Consolidate calls to dependency('libdrm')
Set WITH_LIBDRM when building with libdrm
v2:
Initialize libxserver_dri3 to []
Manually flatten libxserver, since meson doesn't (currently)
Use version_compare rather than circumloctions with dependency()
Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>
Reviewed-by: Eric Anholt <eric@anholt.net>
820a4cbe9f