add freeglut wrap

[kusma]

I created this wrap-file for the mesa-demos repository, and I figured others might be interested in this.

A few details:

1. We provide both "freeglut" and "glut" dependencies. This is because FreeGLUT has it's own API that is an extension of the normal GLUT API.
2. We do a few things differently from the upstream CMake build system, to make things a bit more straight-forward to use.
   • We disable the FREEGLUT_LIB_PRAGMAS option unconditionally. We don't need it, as meson is perfectly capable to forward the correct linker args without it.
   • We don't try to match the libnames. This is really only needed for the FREEGLUT_LIB_PRAGMAS option, which we already disable.
   • No GLES support. I have some untested patches for this, but would prefer to land GL only for now.
   • No Blackberry OS support. There's no first-class support in Meson for this, and it seems... needlessly exotic anyway.
   • No Android support. Possible to add, but depends on GLES support. I don't do Android development, so I think it'd be better if someone who cares about Android and GLUT to work on this. We also don't have Android build-testing on CI, it seems.