Comment # 7 on bug 1198449 from Johannes Meixner

I wished I found more time for things like that
but in practice that never happens.

For me the main problem is that
/usr/share/doc/ghostscript/9.54.0/thirdparty.htm
which is also online at
https://ghostscript.com/doc/9.54.0/thirdparty.htm
does not tell WHY each particular third party library
is included in Ghostscript.

Using a system library instead of Ghostscript's
included library might cause (possibly subtle)
regressions because third party sources that are included
in the Ghostscript sources are (always/sometimes?) modified
by Ghostscript upstream for special Ghostscript needs
or Ghostscript depends on the exact version of the included
third party source so some (possibly subtle) things may fail
when Ghostscript is compiled with the system's library.

E.g. see my comments about lcms2 in ghostscript.spec
and in ghostscript.changes.

I know basically nothing at all about zlib
(except it is used for data-compression)
so I cannot simply do actually useful things
for issues related to zlib in Ghostscript.
I would have to digg into the zlib area
which requires some "extra" time
but that never appears in practice
so such issues just hang...