Daniel,
we really shouldn't be building unix/ on cygwin. In spite of the built-in support, it simply hasn't been vetted and is bound to have vulnerabilities if used for Apache 2.0.
Ideally we should modify the configure.in for cygwin to determine win32/ as the build sources, and toggle -DWIN32. There are probably other side effects, but I'd be happy to help you work through them if you would like to help us put together a patch.
In many cases (see the file lists in the .dsp win32 build files) we zig-zag between win32/ and unix/ in the same tree, and need to see how to do so effectively for cygwin.
If we do this right, the same sources should build on both cygwin and mingw.
Please please discuss this on the cygwin mailing lists before going down this course.
Cygwin is supposed to be unix-like. Packages shouldn't need to start applying win32 specific tricks, and when they do, it often compromizes the unix-like feel that is a major feature of Cygwin.
Max.
