Add guile package

Add diffutils dependency

packages/guile.rb

+require 'package'
+
+class Guile < Package
+  description 'Guile is designed to help programmers create flexible applications that can be extended by users or other programmers with plug-ins, modules, or scripts.'
+  homepage 'http://www.gnu.org/software/guile/'
+  version '2.2.3'
+  source_url 'https://ftp.gnu.org/gnu/guile/guile-2.2.3.tar.xz'
+  source_sha256 '8353a8849cd7aa77be66af04bd6bf7a6207440d2f8722e46672232bb9f0a4086'
+
+  binary_url ({
+  })
+  binary_sha256 ({
+  })
+
+  depends_on 'diffutils' => :build
+  depends_on 'libtool' => :build
+  depends_on 'bdwgc'
+  depends_on 'libffi'
+  depends_on 'libunistring'
+
+  def self.build
+    system './configure',
+           "--prefix=#{CREW_PREFIX}",
+           "--libdir=#{CREW_LIB_PREFIX}",
+           '--disable-dependency-tracking'
+    system 'make'
+  end
+
+  def self.install
+    system "make", "DESTDIR=#{CREW_DEST_DIR}", "install"
+    system "gzip -9 #{CREW_DEST_PREFIX}/share/man/man1/guile.1"
+  end
+end