build: Produce 'guix-config' instead of using compile-time tricks.

* 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.

.gitignore

@@ -120,8 +120,7 @@ GTAGS
 /emacs/Makefile
 /emacs/guix-autoloads.el
 /emacs/guix-helper.scm
-/emacs/guix-init.el
-/emacs/guix-profiles.el
+/emacs/guix-config.el
 /doc/os-config-bare-bones.texi
 /doc/os-config-desktop.texi
 /doc/*.1

configure.ac

@@ -205,8 +205,7 @@ AM_CONDITIONAL([HAVE_EMACS], [test "x$EMACS" != "xno"])
 
 emacsuidir="${guilemoduledir}/guix/emacs"
 AC_SUBST([emacsuidir])
-AC_CONFIG_FILES([emacs/guix-init.el
-                 emacs/guix-profiles.el
+AC_CONFIG_FILES([emacs/guix-config.el
                  emacs/guix-helper.scm])
 
 AC_OUTPUT

emacs.am

@@ -26,11 +26,13 @@ ELFILES =					\
   emacs/guix-help-vars.el			\
   emacs/guix-history.el				\
   emacs/guix-info.el				\
+  emacs/guix-init.el				\
   emacs/guix-list.el				\
   emacs/guix-messages.el			\
   emacs/guix-pcomplete.el			\
   emacs/guix-popup.el				\
   emacs/guix-prettify.el			\
+  emacs/guix-profiles.el			\
   emacs/guix-read.el				\
   emacs/guix-utils.el				\
   emacs/guix.el
@@ -41,9 +43,7 @@ dist_lisp_DATA =				\
   $(ELFILES)					\
   $(AUTOLOADS)
 
-nodist_lisp_DATA =				\
-  emacs/guix-init.el				\
-  emacs/guix-profiles.el
+nodist_lisp_DATA = emacs/guix-config.el
 
 $(AUTOLOADS): $(ELFILES)
 	$(EMACS) --batch --eval						\

emacs/guix-config.el.in

@@ -0,0 +1,31 @@
+;;; guix-config.el --- Compile-time configuration of Guix.
+
+;; Copyright © 2015 Mathieu Lirzin <mthl@openmailbox.org>
+
+;; This file is part of GNU Guix.
+
+;; GNU Guix is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Guix is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Code:
+
+(defconst guix-emacs-interface-directory
+  (replace-regexp-in-string "${prefix}" "@prefix@" "@emacsuidir@"))
+
+(defconst guix-state-directory
+  ;; This must match `NIX_STATE_DIR' as defined in `daemon.am'.
+  (or (getenv "NIX_STATE_DIR") "@guix_localstatedir@/guix"))
+
+(provide 'guix-config)
+
+;;; guix-config.el ends here

emacs/guix-init.el

@@ -1,7 +1,7 @@
+(require 'guix-config)
 (require 'guix-autoloads)
 
-(defvar guix-load-path
-  (replace-regexp-in-string "${prefix}" "@prefix@" "@emacsuidir@")
+(defvar guix-load-path guix-emacs-interface-directory
   "Directory with scheme files for \"guix.el\" package.")
 
 (defcustom guix-package-enable-at-startup t

emacs/guix-profiles.el

@@ -19,12 +19,14 @@
 
 ;;; Code:
 
+(require 'guix-config)
+
 (defvar guix-user-profile
   (expand-file-name "~/.guix-profile")
   "User profile.")
 
 (defvar guix-default-profile
-  (concat (or (getenv "NIX_STATE_DIR") "@guix_localstatedir@/guix")
+  (concat guix-state-directory
           "/profiles/per-user/"
           (getenv "USER")
           "/guix-profile")