I'm trying to build PDL from source into my local perl install and it requires OpenGL

That's not strictly correct - OpenGL is only required if you want your PDL to make use of its graphics capabilities. PDL will still build fine without OpenGL, and there are alternatives to OpenGL re PDL's graphics capabilities (especially on linux, I would think).

The perldl mailing list would probably be the best place to seek out the details about alternatives.

Cheers,
Rob