nano: import homebrew/dupes into core.

Formula/nano.rb

@@ -0,0 +1,44 @@
+class Nano < Formula
+  desc "Free (GNU) replacement for the Pico text editor"
+  homepage "https://www.nano-editor.org/"
+  url "https://www.nano-editor.org/dist/v2.7/nano-2.7.4.tar.gz"
+  sha256 "23ffc2de52d687739fed6dc2fc94df36aa7da7bb52c8740c523fdd7336fdbc8c"
+
+  bottle do
+    sha256 "87672dcd3b034ec2b8d19b3497d4d661a53c216414de1a50f80b2842020725dc" => :sierra
+    sha256 "612cc5c65432e26bef06197b7eeda194f7b42fac62be6e835808c90c52e9d893" => :el_capitan
+    sha256 "7eaed3b3541993a829d1ae17642d9d5b67422150ea6ee719fddbeb675dec816d" => :yosemite
+  end
+
+  head do
+    url "http://git.savannah.gnu.org/r/nano.git"
+    depends_on "automake" => :build
+    depends_on "autoconf" => :build
+  end
+
+  depends_on "pkg-config" => :build
+  depends_on "gettext"
+  depends_on "ncurses"
+
+  def install
+    # Otherwise SIGWINCH will not be defined
+    ENV.append_to_cflags "-U_XOPEN_SOURCE" if MacOS.version < :leopard
+
+    system "./autogen.sh" if build.head?
+    system "./configure", "--disable-debug",
+                          "--disable-dependency-tracking",
+                          "--prefix=#{prefix}",
+                          "--sysconfdir=#{etc}",
+                          "--enable-color",
+                          "--enable-extra",
+                          "--enable-multibuffer",
+                          "--enable-nanorc",
+                          "--enable-utf8"
+    system "make", "install"
+    doc.install "doc/sample.nanorc"
+  end
+
+  test do
+    system "#{bin}/nano", "--version"
+  end
+end