dri/osmesa: automake: include builddir prior to srcdir

Analogous to previous commit.

Cc: "12.0 13.0" <mesa-dev@lists.freedesktop.org>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
(cherry picked from commit 6ba96bdcabc4c9c89827603907aba1b7dd5e9972)
1 file changed