Add license headers to files

[jbauman42]

Would it be possible to add license headers to these files?

doc/ghdeploydoxy.sh meson_options.txt doc/Doxyfile.in pkgconfig/libva-drm.pc.in pkgconfig/libva-glx.pc.in pkgconfig/libva-wayland.pc.in pkgconfig/libva-x11.pc.in pkgconfig/libva.pc.in

I don't know whether it's possible to modify the .in files (without breaking them), but I think modifying the .sh and .txt files should be technically feasible.