automating %load-path

[Kalle Olavi Niemitalo <tosi at stekt dot oulu dot fi>]

I would like to make Guile Emacs automatically insert its Scheme
directories in the %load-path of Guile, so that users don't have
to do that in ~/.emacs.scm.  My plan:

1. Add a new variable $schemepath in configure.in.

2. Add a new macro PATH_SCMLOADSEARCH in src/epaths.in.  If we
   don't support Scheme in temacs, we don't need
   PATH_SCMDUMPLOADSEARCH.

3. Make the epaths-force target in Makefile.in store $schemepath
   in epaths.h.

4. Make init_guileapi() in src/guileapi.c add the
   PATH_SCMLOADSEARCH directories in %load-path.  I'm not very
   familiar with Guile's C API but I'll learn.  :-)

5. Create a new module (emacs init) and place all Scheme
   initialization code there.  This could load (emacs io).

6. Load (emacs init) from lisp/startup.el.

The Emacs files src/epaths.in and Makefile.in would have to be
added in CVS.  I currently have only Emacs 20.5, not 20.6 so
could you add those files, Keisuke?  I can insert the
modification comments.