New formula: logtalk

Closes Homebrew/homebrew#8220.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Formula/logtalk.rb

@@ -0,0 +1,38 @@
+require 'formula'
+
+class Logtalk < Formula
+  url 'http://logtalk.org/files/lgt2432.tar.bz2'
+  md5 'b5698033aca3c5173b7afe0ce4e84782'
+  version '2.43.2'
+  homepage 'http://logtalk.org'
+
+  case
+  when ARGV.include?("--swi-prolog")
+    depends_on 'swi-prolog'
+  when ARGV.include?("--gnu-prolog")
+    depends_on 'gnu-prolog'
+  else
+    depends_on 'gnu-prolog'
+  end
+
+  case
+    when ARGV.include?("--use-git-head")
+      head 'git://github.com/pmoura/logtalk.git'
+    else
+      head 'http://svn.logtalk.org/logtalk/trunk', :using =>   :svn
+  end
+
+  def options
+     [
+       ["--swi-prolog", "Build using SWI Prolog as backend."],
+       ["--gnu-prolog", "Build using GNU Prolog as backend. (Default)"],
+       ["--use-git-head", "Use GitHub mirror."]
+     ]
+  end
+
+  def install
+    system "scripts/install.sh #{prefix}"
+    man1.install Dir['man/man1/*']
+    bin.install Dir['bin/*']
+  end
+end