FreeBSD adjusted kernel zlib is moved into netgraph.
contrib/zlib is moved to sys/contrib/zlib and adjusted in both user land and kernel.
zlib copy in zfs is removed and uses sys/contrib/zlib.
CTF is modified to use uncompress().
Cleaned up sys/mips.
arm5 is untouched.
gzipped a.out execution is untouched although it is broken in 12-stable/13-current.
kgzip and kgzldr are removed.
Refer to sys/modules/zlib/README in the changeset.