portage: fork portage to test xattr-install

git-svn-id: http://pentoo.googlecode.com/svn@5785 04556701-5d27-2e10-b29c-201e0903c0fa
profile: keyword xattr for testing on the build system (and beyond if you like)

git-svn-id: http://pentoo.googlecode.com/svn@5786 04556701-5d27-2e10-b29c-201e0903c0fa