utils: move include directives before extern "C" wrapper
utils: move include directives before extern "C" wrapper

Analogous to last two commits.

Signed-off-by: Emil Velikov <4c996f2f093ddd0585a556460b4cc3ba555546ef@gmail.com>
Reviewed-by: Pekka Paalanen <0f6ae7001e34c37b02fb2c1c2573ddf8f442136a@collabora.co.uk>
Reviewed-by: Quentin Glidic <241385a0e41ea713327e189bce1062decf7c1eb5@sardemff7.net>

sir-murray/wayland,sir-murray/wayland,sir-murray/wayland