V08zpty.ztst hangs on Cygwin

[İsmail Dönmez <ismail@xxxxxxxxx>]

Hi,

While running make check I noticed that V08zpty.ztst was hanging. Turns out
that second part of the test is hanging. The minimal reproducer is:

zmodload zsh/zpty
zpty cat cat
print a line of text | zpty -w cat
var=
zpty -r cat var && print -r -- ${var%%$'\r\n'}
zpty -d cat # <--- HANGS

I am not sure if Cygwin is a supported platform but any help would be
appreciated.

Thanks!