debug: Introduce VREND_DEBUG_ENABLED flag

VREND_DEBUG_ENABLED represents if debugging features are enabled and is
controlled by NDEBUG macro. By using VREND_DEBUG_ENABLED in
an if statement instead of using NDEBUG in ifdef, the compiler can
validate the content of the conditional and know its variable usage to
avoid meaningless warnings.

Signed-off-by: Akihiko Odaki <akihiko.odaki@gmail.com>
Part-of: <https://gitlab.freedesktop.org/virgl/virglrenderer/-/merge_requests/715>
3 files changed