Mesa 18.0 branchpoint
automake: small cleanup after the meson.build inclusion

Namely extend the EXTRA_DIST list, instead of re-assigning it and bring
back a file dropped by mistake.

Fixes: 436ed65d38d ("autotools: include meson build files in tarball")
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
4 files changed