It's only used by dix internally (actually just dixfonts.c - since at
least 25 years now), thus no need to keep it in global include directory.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1388>
Enrico Weigelt, metux IT consult