Zlib Upgrade in kernel

[Bruce Evans]

On Sat, 4 May 2019, Yoshihiro Ota wrote:

> After I posted zlib upgrade effort about a month ago, I got feedbacks and went through iterations of changes.
> https://reviews.freebsd.org/D19706 is ready for another review.
>
> I have few unfamilar peices.  If anyone can comment, that will be great.
>
> ...
> Q.2 Does anyone run gzipped a.out format on the latest systems?
>   I was able to run a.out and  gzipped a.out on FreeBSD 2.2.9.
>    I ran a.out grabbed fron 2.2.9 on 12-STABLE and 13-CURRENT but gzipped a.out didn't start.

Seems unlikely.  imgact_gzip only ever worked for aout, and has been broken
for that for many years.  Last time I looked (in 2017), the first failure in
imgact_gzip.c was in vm_mmap(exec_map, ...) last changed in r231885 in 2012.
This failed with error 11 (EDEADLK).

I use old aout utilities often, but don't want gzip (or zlib) in the kernel
for aout (or anything).

Bruce