Simplify definition of GUILE

Simplify definition of GUILE

This patch sets GUILE to just plain 'guile'.

In the distant ("devo") past, the top-level build did support building
Guile in-tree.  However, I don't think this really works any more.
For one thing, there are no build dependencies on it, so there's no
guarantee it would actually be built before the uses.

This patch also removes the use of "-s" as an option to cgen scheme
scripts.  With my latest patch upstream, this is no longer needed.

After the upstream changes, either Guile 2 or Guile 3 will work, with
or without the compiler enabled.

2023-08-24  Tom Tromey  <tom@tromey.com>

	* cgen.sh: Don't pass "-s" to cgen.
	* Makefile.in: Rebuild.
	* Makefile.am (GUILE): Simplify.