[zlib][build] Handle CentOS quirks

Apparently some environments (e.g. CentOS) require to explicitly link
with libpthread otherwise build/link of zlib works fine but zlib_bench
linking fails.

Bug: 1381000
Change-Id: Idfc1984dc096672255bf43f141572c222147f681
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4198473


Commit-Queue: Adenilson Cavalcanti <cavalcantii@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Reviewed-by: Hans Wennborg <hans@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1097968}
NOKEYCHECK=True
GitOrigin-RevId: 767a83e626f09cf18013e88453514c692442dceb