My collection of official and inofficial cygwin package patches and scripts is now also at google code: http://code.google.com/p/cygwin-rurban
Browse the cygwin Perl build and patches (a custom build-system):
http://code.google.com/p/cygwin-rurban/source/browse/#svn/trunk/release/perl>
Browse the cygwin Parrot patches:
http://code.google.com/p/cygwin-rurban/source/browse/#svn/trunk/release/parrot>