macrofied kernel.spec

[Roland McGrath]

> I've been intending to do the same. Definitely nice to nuke a bunch of
> the duplication, but at least in patch form, its not the easiest thing
> to read and fully comprehend.

Yes, don't try to read the patch.  (It also gratuitously reorders a couple
things, because that makes the final kernel.spec easier to read.)

> Okay, spent a while looking at a patched spec file. I think I mostly
> grok everything, though some of the magic I'm not sure I've ever seen
> before. I might even feel comfortable trying to fix things iff Roland
> does leave the country or have an accident... ;)

If there is anything that you think should have more comments, let me know.
I didn't bother with any comments explaining the % syntax being used.
But probably there should be some.  Like most things in rpm, 80% of the
relevant details are not documented anywhere.