Hi Neil, there exists already packages in cygwin for rakudo and parrot. Reini Urban put them in. I don't not know about the current version number.
But rakudo and parrot should build out of the box under Windows. You don't need cygwin. The last time I build Rakudo under Windows I installed: MinGW, git and subversion With that it builds out of the box the last time I tried it. If you need to build under cygwin, may be Reini Urban will help. -- Gerd