Fixes <http://bugs.gnu.org/21127>.
* emacs/guix-backend.el: Use guix-config.
(guix-guile-program): Move to ...
* emacs/guix-config.el.in (guix-guile-program): ... here. Use Guile
program file name from compile-time instead of depending on PATH.
* emacs/guix-{init,profiles}.el.in: Rename to ...
* emacs/guix-{init,profiles}.el: ... these. New files.
Use 'guix-config'.
* emacs/guix-config.el.in: New file.
* emacs.am (nodist_lisp_DATA): Add it. Move them to ...
(ELFILES): ... here.
* .gitignore, configure.ac: Adjust accordingly.