The Pike Gz module is missing on Debian 12 because the configure
script believes the system zlib is broken.
It runs src/modules/Gz/gz_test.c, which errors out with:
inflate should report DATA_ERROR
gz_test.c is an edited version of test/example.c from the zlib
distribution. Upstream commit 0d36ec47 changes the expected outcome of
inflate in this situation from Z_DATA_ERROR to Z_STREAM_END.
The gz_test.c should probably accept both values, in order to be
compatible with both old and new versions of zlib.
0d36ec47 was first included in zlib version 1.2.12 and 1.3, so the
Pike Gz module is only available if you are using zlib version 1.2.11
or older. Debian 12 ships with zlib 1.2.13.
(I have not investigated if the Pike usage of zlib depends on the old
behavior. There is a theoretical risk that this really is an
incompatible change and that more changes are needed to the Pike
code.)
