Strange, I did an apt-get install fpc then apt-get install lazarus and they just worked, weeks? ago.
Broken recently? Mine is Laz 2.0.0. fpc 3.0.4
Also it helps if you install freeGLUT.
I have compiled some OpenGL fpc examples that use glut, did not even need Lazarus.
Working through the fpc OpenGL tutorials, they work.
Some stuff does not, too many libs, GL, GLU, GLX, GLEW, Glut, FreeGlut, it get confusing at times
With Tim's shadertoy, mesa demos and geexlabs demos/shader/utils, seems to be lots of stuff that just works in C.
The trick seems to be to find examples that use what we have without being too old or too new.
I would love to have a GLSL compiler in Free Pascal, for obvious reasons
A Pascal version of freeGlut might be handy but making it a lib???.a and linking it might work too.
I know FPC and others langs like Go, Rust can use C files, I just don't know how yet.
You know Pi's are now Desktop Computers when stuff just works.
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges