Add example package for the hello program

See: https://www.gnu.org/software/guix/blog/2018/a-packaging-tutorial-for-guix/

Signed-off-by: Collin J. Doering <collin@rekahsoft.ca>

hello.scm

@@ -0,0 +1,42 @@
+;; (C) Copyright Collin J. Doering 2019
+;;
+;; This program 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.
+;; 
+;; This program 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/>.
+
+;; File: hello.scm
+;; Author: Collin J. Doering <collin.doering@rekahsoft.ca>
+;; Date: Jan 31, 2019
+
+(use-modules (guix packages)
+             (guix download)
+             (guix build-system gnu)
+             (guix licenses))
+
+(package
+  (name "my-hello")
+  (version "2.10")
+  (source (origin
+            (method url-fetch)
+            (uri (string-append "mirror://gnu/hello/hello-" version
+                                ".tar.gz"))
+            (sha256
+             (base32
+              "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
+  (build-system gnu-build-system)
+  (synopsis "Hello, Guix world: An example custom Guix package")
+  (description
+   "GNU Hello prints the message \"Hello, world!\" and then exits.  It
+serves as an example of standard GNU coding practices.  As such, it supports
+command-line arguments, multiple languages, and so on.")
+  (home-page "https://www.gnu.org/software/hello/")
+  (license gpl3+))