[Bug bootstrap/79771] [7 Regression] in-tree zlib breaks build

[daniel.santos at pobox dot com]

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.