xmlconfig: use the portable __VA_ARGS__

Follow the example used through mesa and use "..." + "__VA_ARGS__".
The former tends to be more common and portable.

v2: use ##__VA_ARGS__ (Eric)

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
1 file changed