[freeglut] enable building on non-win32

[cenit]

port patch from #5169

[vicroms]

Hi @cenit

We have a green check, but it is a false positive. For some reason CI didn't rebuild freeglut for Mac OS, I'll delete the cached archive and trigger a new build for it.

Fail on Mac OS X due to missing system dependencies.

Freeglut currently requires the following libraries from the system package manager:
    opengl
    glu
    libx11

These can be installed on Ubuntu systems via apt-get install libxi-dev libgl1-mesa-dev libglu1-mesa-dev mesa-common-dev

[vicroms]

Thanks for the PR!

freeglut now works on x64-osx

x64-osx	master	test	notes
gl2ps	Skip	Pass
freeglut	Fail	Pass
theia	Skip	Fail

[cenit]

I hope that theia will be fixed in its own separate PR soon :)