Pull up following revision(s) (requested by tsutsui in ticket #375):
common/dist/zlib/inflate.c: revision 1.6
Restore a local change (in rev1.4) that was lost on zlib 1.12.10 merge.
The rev 1.4 changelog:
Disable a sanity check output buffer != NULL in _STANDALONE case.
Some kernels are loaded at address 0x0 by bootloaders and
output buffer address could be zero in such case.
Fixes "read text" errors on loading install floppy of NetBSD/news68k 4.0,
reported by KIYOHARA Takashi on port-news68k.
This problem may also affect other m68k ports which use a gzipped install
kernel and kernel text address located at PA 0x0.
Should be pulled up to netbsd-8.

(martin)