gnu: Add GNU Prolog.

* gnu/packages/gprolog.scm: New file.
* Makefile.am (MODULES): Add it.

Makefile.am

@@ -78,6 +78,7 @@ MODULES =					\
   gnu/packages/gnupg.scm			\
   gnu/packages/gnutls.scm			\
   gnu/packages/gperf.scm			\
+  gnu/packages/gprolog.scm			\
   gnu/packages/groff.scm			\
   gnu/packages/gsasl.scm			\
   gnu/packages/guile.scm			\

gnu/packages/gprolog.scm

@@ -0,0 +1,72 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2013 Nikita Karetnikov <nikita@karetnikov.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 GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu packages gprolog)
+  #:use-module (guix licenses)
+  #:use-module (guix packages)
+  #:use-module (guix download)
+  #:use-module (guix build-system gnu))
+
+(define-public gprolog
+  (package
+    (name "gprolog")
+    (version "1.4.2")
+    (source
+     (origin
+      (method url-fetch)
+      (uri (string-append "http://www.gprolog.org/gprolog-"
+                          version ".tar.gz"))
+      (sha256
+       (base32
+        "0y25c2gwz41i6g28qyfjklrmanzgk0c8cr4jn2s7s8qgd9dnm1fm"))))
+    (build-system gnu-build-system)
+    (arguments
+     `(#:phases (alist-cons-before
+                 'configure 'change-dir-n-fix-shells
+                 (lambda _
+                   (chdir "src")
+                   (substitute* "configure"
+                     (("-/bin/sh")  (string-append "-"  (which "sh")))
+                     (("= /bin/sh") (string-append "= " (which "sh")))))
+                 %standard-phases)))
+    (home-page "https://www.gnu.org/software/gprolog/")
+    (synopsis
+     "GNU Prolog, a free Prolog compiler with constraint solving over
+finite domains")
+    (description
+     "GNU Prolog is a free Prolog compiler with constraint solving over
+finite domains developed by Daniel Diaz.
+
+GNU Prolog accepts Prolog+constraint programs and produces native
+binaries (like gcc does from a C source).  The obtained executable is
+then stand-alone.  The size of this executable can be quite small since
+GNU Prolog can avoid to link the code of most unused built-in
+predicates.  The performances of GNU Prolog are very
+encouraging (comparable to commercial systems).
+
+Beside the native-code compilation, GNU Prolog offers a classical
+interactive interpreter (top-level) with a debugger.
+
+The Prolog part conforms to the ISO standard for Prolog with many
+extensions very useful in practice (e.g., global variables, OS
+interface, sockets).
+
+GNU Prolog also includes an efficient constraint solver over finite domains.
+This opens contraint logic programming to the user combining the power of
+constraint programming to the declarativity of logic programming.")
+    (license (list gpl2+ lgpl3+))))