Since we're not using C++ code, thus no trouble w/ name mangling, we don't
need explicit extern "C" { ... } sections in the code. (If we would, we
have to have it in many other places, too)
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1331>