gnu: Add entr.

* gnu/packages/entr.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add it.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

gnu/local.mk

@@ -108,6 +108,7 @@ GNU_SYSTEM_MODULES =				\
   gnu/packages/enchant.scm			\
   gnu/packages/engineering.scm			\
   gnu/packages/enlightenment.scm		\
+  gnu/packages/entr.scm				\
   gnu/packages/fcitx.scm			\
   gnu/packages/feh.scm                          \
   gnu/packages/figlet.scm			\

gnu/packages/entr.scm

@@ -0,0 +1,66 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2016 Matthew Jordan <matthewjordandevops@yandex.com>
+;;; Copyright © 2016 Ludovic Courtès <ludo@gnu.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 entr)
+  #:use-module (guix licenses)
+  #:use-module (guix packages)
+  #:use-module (guix download)
+  #:use-module (guix build-system gnu))
+
+(define-public entr
+  (package
+    (name "entr")
+    (version "3.5")
+    (source (origin
+              (method url-fetch)
+              (uri (string-append "http://entrproject.org/code/entr-"
+                                  version ".tar.gz"))
+              (sha256
+               (base32
+                "05k4jyjna0pr2dalwc1l1dhrcyk6pw7hbss7jl4ykwfadcs5br73"))))
+    (build-system gnu-build-system)
+    (arguments
+     `(#:test-target "test"
+       #:phases (modify-phases %standard-phases
+                  (replace 'configure
+                    (lambda* (#:key outputs #:allow-other-keys)
+                      (let ((out (assoc-ref outputs "out")))
+                        (setenv "CONFIG_SHELL" (which "bash"))
+                        (setenv "CC" (which "gcc"))
+                        (setenv "DESTDIR" (string-append out "/"))
+                        (setenv "PREFIX" "")
+                        (setenv "MANPREFIX" "man")
+                        (zero? (system* "./configure")))))
+                  (add-before 'build 'remove-fhs-file-names
+                    (lambda _
+                      ;; Use the tools available in $PATH.
+                      (substitute* "entr.c"
+                        (("/bin/cat") "cat")
+                        (("/usr/bin/clear") "clear")))))))
+    (home-page "http://entrproject.org/")
+    (synopsis "Run arbitrary commands when files change")
+    (description
+     "entr is a zero-configuration tool with no external build- or run-time
+dependencies.  The interface to entr is not only minimal, it aims to be simple
+enough to create a new category of ad hoc automation.  These micro-tests
+reduce keystrokes, but more importantly they emphasize the utility of
+automated checks.")
+
+    ;; Per 'LICENSE', portability code under missing/ is under BSD-2.
+    (license isc)))