Split gl.go into separate pieces

[pwaller]

No description provided.

[pwaller]

So I've made a first attempt above. The idea is a little fraught because apart from the objects and a few other things, it's not totally clear how best to split things, so you're still left with a giant gl.go file. Secondly, every file using the C api needs the cgo directives, which is unfortunate, especially since they might need updating for windows/mac.

[ghost]

The repeating CGO directives can probably be moved to a separate gl.h file. You then only have to include that one. The #cgo bits only have to be listed once.

[pwaller]

Unfortunately, that doesn't work for the #cgo directive :-(

[ghost]

Weird. It seems to be fine in the glfw package. Only glfw.go carries the #cgo bits.

[pwaller]

Ah, of course.

[ghost]

Looks good to me. If @banthar has no further comments, this is good to go as far as I'm concerned.