build: Add "build-aux/guix.scm".

* build-aux/guix.scm: New file.
* Makefile.am (EXTRA_DIST): Add it.

Makefile.am

@@ -143,6 +143,7 @@ uninstall-hook:
     fi
 
 EXTRA_DIST = \
+  build-aux/guix.scm \
   .version \
   $(TESTS)
 

build-aux/guix.scm

@@ -0,0 +1,66 @@
+;;;; guix.scm -- Guix package definition
+;;; Copyright © 2016 Mathieu Lirzin <mthl@gnu.org>
+;;;
+;;; This file is part of GNU Mcron.
+;;;
+;;; GNU Mcron 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 Mcron 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 GNU Mcron.  If not, see <http://www.gnu.org/licenses/>.
+
+(use-modules (ice-9 popen)
+             (ice-9 rdelim)
+             (gnu)
+             (guix)
+             (srfi srfi-1))
+
+(define (keep-mcron-file? file stat)
+  ;; Return #t if FILE in Mcron repository must be kept, #f otherwise. FILE
+  ;; is an absolute file name and STAT is the result of 'lstat' applied to
+  ;; FILE.
+  (not (or (any (λ (str) (string-contains file str))
+                '(".git" "autom4te" "Makefile.in" ".go" ".log"
+                  "stamp-vti" ".dirstamp"))
+           (any (λ (str) (string-suffix? str file))
+                '("trs""configure" "Makefile" "config.status" "pre-inst-env"
+                  "aclocal.m4" "bin/cron" "bin/mcron" "bin/crontab" "config.cache"
+                  "guix.scm")))))
+
+(define %srcdir
+  (or (current-source-directory) "."))
+
+(define (git-version-gen)
+  ;; Return a string containing Cuirass version number.
+  (let* ((cmd  "git-version-gen .version")
+         (port (open-input-pipe (string-append %srcdir "/" cmd)))
+         (str  (read-line port)))
+    (close-pipe port)
+    str))
+
+(package
+  (inherit (specification->package "mcron2"))
+  (version (git-version-gen))
+  (source (local-file (dirname %srcdir) #:recursive? #t
+                      #:select? keep-mcron-file?))
+  (arguments
+   '(#:phases
+     (modify-phases %standard-phases
+       (add-before 'configure 'bootstrap
+         (λ _ (zero? (system* "autoreconf" "-vfi")))))))
+  (inputs
+   `(("guile" ,(specification->package "guile@2.0"))))
+  (native-inputs
+   `(("autoconf" ,(specification->package "autoconf"))
+     ("automake" ,(specification->package "automake"))
+     ("help2man" ,(specification->package "help2man"))
+     ("pkg-config" ,(specification->package "pkg-config"))
+     ("texinfo" ,(specification->package "texinfo"))
+     ("which" ,(specification->package "which")))))