otx: Patch MacOS SDK paths

otx is hardcoded to use the MacOSX10.6 SDK which is no longer available in
Mountain Lion. By replacing this with MacOSX#{MacOS.version} the package can
be successfully built even on 10.8.

Closes Homebrew#15879.

Signed-off-by: Charlie Sharpsteen <source@sharpsteen.net>

Library/Formula/otx.rb

@@ -7,6 +7,10 @@ class Otx < Formula
   depends_on :xcode # For working xcodebuild.
 
   def install
+    inreplace 'otx.xcodeproj/project.pbxproj' do |s|
+      s.gsub! "MacOSX10.6.sdk", "MacOSX#{MacOS.version}.sdk"
+    end
+
     system 'xcodebuild SYMROOT=build'
     build = buildpath/'build/Release'
     bin.install build+"otx"