gnu-chess: import from homebrew/games.

Formula/gnu-chess.rb

@@ -0,0 +1,58 @@
+class GnuChess < Formula
+  desc "GNU Chess"
+  homepage "https://www.gnu.org/software/chess/"
+  url "https://ftpmirror.gnu.org/chess/gnuchess-6.2.4.tar.gz"
+  mirror "https://ftp.gnu.org/gnu/chess/gnuchess-6.2.4.tar.gz"
+  sha256 "3c425c0264f253fc5cc2ba969abe667d77703c728770bd4b23c456cbe5e082ef"
+
+  bottle do
+    sha256 "411c317415947009b6049a01eba5f982b3a490f6bf55e11666af6e6c8b8ffe18" => :sierra
+    sha256 "65ee081879182d9ebd12eef9d737bc12ad22247ff27ecd339ecb2f76e1434cbe" => :el_capitan
+    sha256 "20c1c10b54746fb09eeb0101b014d39fb6196b0668ed5e6e9b9acd0b6488b970" => :yosemite
+  end
+
+  head do
+    url "svn://svn.savannah.gnu.org/chess/trunk"
+    depends_on "autoconf" => :build
+    depends_on "automake" => :build
+    depends_on "help2man" => :build
+    depends_on "gettext"
+  end
+
+  option "with-book", "Download the opening book (~25MB)"
+
+  resource "book" do
+    url "https://ftpmirror.gnu.org/chess/book_1.02.pgn.gz"
+    sha256 "deac77edb061a59249a19deb03da349cae051e52527a6cb5af808d9398d32d44"
+  end
+
+  def install
+    if build.head?
+      system "autoreconf", "--install"
+      chmod 0755, "install-sh"
+    end
+
+    system "./configure", "--disable-dependency-tracking",
+                          "--prefix=#{prefix}"
+    system "make", "install"
+
+    if build.with? "book"
+      resource("book").stage do
+        doc.install "book_1.02.pgn"
+      end
+    end
+  end
+
+  if build.with? "book"
+    def caveats; <<-EOS.undent
+      This formula also downloads the additional opening book.  The
+      opening book is a PGN file located in #{doc} that can be added
+      using gnuchess commands.
+    EOS
+    end
+  end
+
+  test do
+    assert_equal "GNU Chess #{version}", shell_output("#{bin}/gnuchess --version").chomp
+  end
+end