Name variables in GL errors

Follow up for #883

We check arguments using helper functions like this: CheckGE!GLuint(end, start)

This will generate error message which includes the two relevant values, so the user should be able to tell which of the function arguments is incorrect based on that. It would be more user friendly to also include the argument as string.

If this was C++, we could just use macro CHECK_GE(end, start) which stringifies the argument and includes it in the error message. Ideally the language should support something similar.