Does OpenGL specify that constants are any particular value?

So I wouldn't be stupid enough to ask this in general, but here's the situation. I'm in a compilers class, and now that we've finished a compiler for our designed language, we need to write a nontrivial program in it. I'm doing an OpenGL spinning cube, to show off the OpenGL bindings I'm working on.

But I've run into some problems. Mostly, I can't just pull in the OpenGL headers, and in any case I don't need everything in there, but this prevents me from having any of the useful constants (GL_FLOAT, GL_COLOR_BUFFER_BIT, etc).

So I'm wondering - are the #define'd constants the same from machine to machine, and OS to OS? In other words, are the constants themselves part of the GL standard, or left as symbols?

Thanks!