http://bugs.winehq.org/show_bug.cgi?id=21206
--- Comment #6 from Dan Kegel dank@kegel.com 2010-01-10 08:46:18 --- Here's a possible plan of attack for finding the change in cygwin's setup that broke wine compatibility:
1) verify that installing gvim fails with current cygwin setup but succeeds with old cygwin setup *on same snapshot of cygwin repo* by using -X option and pasting ftp://www.fruitbat.org/pub/cygwin/circa/2009/09/08/111037 into the repository field in the cygwin setup, then installing gvim. I think current setup will put up an error dialog halfway through, but old setup will work.
2) learn how to build setup.exe from svn, see http://sourceware.org/cygwin-apps/setup.html
3) verify that building a setup.exe from September's sources works, but that building one from today's sources fails
4) binary search
5) profit!