xspin GUI 5.2.3

A TCL/TK-based GUI for the Spin model checker.

Manually installing xspin on Mac OS X requires edits to the script, as detailed
at http://spinroot.com/spin/Man/README.html. The included DATA patch automates
this.

(My thanks go to adamv, who pointed out how to simplify this formula.)

Formula/xspin.rb

@@ -0,0 +1,44 @@
+require 'formula'
+
+class Xspin <Formula
+  url 'http://spinroot.com/spin/Src/xspin523.tcl'
+  homepage 'http://spinroot.com/spin/Src/index.html'
+  md5 '893eb05798802cea4f281daaf34ce190'
+
+  depends_on 'spin'
+
+  def patches
+    DATA
+  end
+
+  def install
+    version='523'
+
+    fname = "xspin#{version}.tcl"
+
+    inreplace fname, "CELLAR", prefix
+
+    FileUtils.mv fname, "xspin"
+    bin.install "xspin"
+  end
+end
+__END__
+diff --git a/xspin523.tcl b/xspin523.tcl
+old mode 100644
+new mode 100755
+index 73fc6bf..444b0ad
+--- a/xspin523.tcl
++++ b/xspin523.tcl
+@@ -1,8 +1,9 @@
+-#!/bin/sh
++#!/usr/bin/wish -f
+ # the next line restarts using wish \
+-exec wish c:/cygwin/bin/xspin -- $*
++exec wish CELLAR/bin/xspin -- $*
++
++ cd	;# enable to cd to home directory by default
+ 
+-# cd	;# enable to cd to home directory by default
+ 
+ # on PCs:
+ # adjust the first argument to wish above with the name and