glx/windows: automake: include builddir prior to srcdir

Analogous to previous commit.

Cc: "12.0 13.0" <mesa-dev@lists.freedesktop.org>
Cc: Jon Turney <jon.turney@dronecode.org.uk>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
(cherry picked from commit 912b4f5472007dbd06c922cb1c315cb4814c4010)
1 file changed