https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79771
Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> --- If this comes from upstream, then most likely upstream zlib doesn't build on cygwin64 either. So either you have too old cygwin and newer one supports it, or it would be nice to figure out why this changed upstream.