Hi,

An old bug.  Here Mike notes that the manual said "guile-config is
deprecated", but that guile.m4 still used it.

To solve that, I fixed the docs to be say "will be deprecated", and went
to look at the .m4.  I ended up rewriting it.  The new guile.m4 lets you
choose a version, which is nice.  It also checks to make sure that the
Guile found via checking for GUILE_FLAGS was the same as the Guile found
via checking for GUILE_PROGS.

I pushed it to a branch a year ago but it never got review.  Here's the
patch, rebased and attached.  I'll commit it soon if there are no
objections.

Regards,

Andy