meson: Use dependency.partial_dependency()

It avoids calling pkg-config which was searched for in a wrong way, thus
breaking setup where unprefixed pkg-config was banned (e.g. on Exherbo).

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Fixes: 53f9131205a63fa8b282ab2a7e96c48209447da0
       ("meson: fix getting cflags from pkg-config")

Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4701>
1 file changed