Comment # 9 on bug 1198449 from Johannes Meixner

What you praise as "made the hard work"
is only one single step that only shows
that with current Ghostscript sources
and our current zlib version 1.2.11
in openSUSE:Factory, SLE15 and Leap 15.2
things could match - provided we do not have patches
in our zlib - so all could be well currently
BUT
we do have patches in our zlib
and even if all would be well currently
things may fall apart in the future.

I experienced such kind of quick and dirty contributions
way too often in the past and then it is always me alone
who must later clean up the mess when subtle regressions
appear for our users because of careless "optimizations"
by SUSE contributors.

If you would be willing to co-maintain Ghostscript
when it is built with our zlib in the future your
https://build.opensuse.org/request/show/969841 
would be "just acceptable" by me - i.e. I mean it would
be you who checks each time when Ghostscript upgrades
or when our zlib changes if things still fit together
and it is you who talks to Ghostscript upstream to get
an understanding if all should be well for Ghostscript
with basically any (reasonable up to date) zlib version.

FYI:
The included third-party software sources in Ghostscript
are a pain and an annoyance which I wished to clean up
together with Ghostscript upstream but (as written above):
I wished I found more time for things like that
but in practice that never happens.