Fixed SIP version number

The build.py script which prepares SIP for configuration and installation
requires the presence of Mercurial's `.hg` directory in order to determine the
version number from the tag list.  Without this directory it sets the SIP
version number to "0.1-unknown" which causes things like PyQt to fail
complaining that the SIP version number is too small.

This change includes a small patch to build.py that fixes the version number so
that it reads 4.11.1 which is the current version.

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

Formula/sip.rb

@@ -6,6 +6,12 @@ class Sip <Formula
   head 'http://www.riverbankcomputing.co.uk/hg/sip', :using => :hg
   homepage 'http://www.riverbankcomputing.co.uk/software/sip'
 
+  unless ARGV.include? '--HEAD'
+    def patches
+      DATA
+    end
+  end
+
   def install
     # Force building against System python, because we need a Framework build.
     # See: http://github.com/mxcl/homebrew/issues/issue/930
@@ -23,3 +29,29 @@ class Sip <Formula
     EOS
   end
 end
+__END__
+Patch to allow the SIP build.py script to generate a reasonable version number
+without the .hg directory from the Mercurial repository.
+
+diff --git a/build.py b/build.py
+index 927d7f1..fdf13a3 100755
+--- a/build.py
++++ b/build.py
+@@ -179,7 +179,7 @@ def _get_release():
+         changelog = None
+         name = os.path.basename(_RootDir)
+ 
+-        release_suffix = "-unknown"
++        release_suffix = ""
+         version = None
+ 
+         parts = name.split('-')
+@@ -192,7 +192,7 @@ def _get_release():
+ 
+     # Format the results.
+     if version is None:
+-        version = (0, 1, 0)
++        version = (4, 11, 1)
+ 
+     major, minor, micro = version
+