https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79771
--- Comment #3 from Daniel Santos <daniel.santos at pobox dot com> --- I'm guessing that either they didn't test on Cygwin or they tested on a pre-release version or I have some local/environmental issue, although my environment was just recently generated. Upstream is at 1.2.11 and the latest zlib available in Cygwin is 1.2.8-3, which does not have this patch, but I am not an expert in Cygwin. _wopen is an ms-proprietary function and I presumed that it not being exported in Cygwin was intentional, although I could be wrong. It's probably a good idea to send it upstream.
