Added gnu-chess formula

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Formula/gnu-chess.rb

@@ -0,0 +1,61 @@
+require 'formula'
+
+class GnuChess <Formula
+  url 'http://ftp.gnu.org/pub/gnu/chess/gnuchess-5.07.tar.gz'
+  homepage 'http://www.gnu.org/software/chess/'
+  md5 '259da00aa559e5624c65279484fccaf7'
+
+  def patches
+    # v4 of the gcc compiler uncovered an error in the code that should be corrected in
+    # the 5.08 version of gnuchess.
+    #
+    # The error:
+    # input.c:95: error: static declaration of ‘input_thread’ follows non-static declaration
+    #
+    # The patch removes 'static' from the declaration in input.c.  See msg at
+    # http://www.mail-archive.com/bug-gnu-chess@gnu.org/msg00218.html
+    DATA
+  end
+
+  def install
+    # Opening book for gnuchess.  This can be put in the doc directory and the
+    # user can optionally add the opening book.  The README has details on
+    # adding the opening book.
+    book_url = "http://ftp.gnu.org/pub/gnu/chess/book_1.01.pgn.gz"
+    ohai "Downloading #{book_url}"
+    curl book_url, "-O"
+
+    system "./configure", "--disable-debug", "--disable-dependency-tracking", "--prefix=#{prefix}"
+    system "make"
+    ENV.j1 # Prevents a "file already exists" warning
+    system "make install"
+    doc.install Dir['doc/*']
+    doc.install ['TODO', 'book_1.01.pgn.gz', 'book']
+  end
+
+  def caveats
+    <<-EOS.undent
+      The README file contains a manual for use:
+      
+        #{doc}/README
+      
+      This formula also downloads the additional opening book.  The opening
+      book is a gzipped PGN file that can be added using gnuchess commands.
+      The book_*.pgn.gz file is located in the same directory as the README.
+      See the README for using the `book add' command.
+    EOS
+  end
+end
+__END__
+diff --git a/src/input.c b/src/input.c
+index 1fb9be3..5f0ff79 100644
+--- a/src/input.c
++++ b/src/input.c
+@@ -92,7 +92,7 @@ void getline_standard(char *p)
+   fgets(inputstr, MAXSTR, stdin);
+ }
+
+-static pthread_t input_thread;
++pthread_t input_thread;
+
+ /* Mutex and condition variable for thread communication */