[zlib][build] Remove fdopen #defines in zutil.h.

The latest version of Clang changed what macros it predefines on Apple
targets, causing errors about predefined macros in zlib.

See:
https://github.com/madler/zlib/commit/4bd9a71f3539b5ce47f0c67ab5e01f3196dc8ef9

Bug: 1519899
Change-Id: Ie75ef4078f2c86d89ba6c036ddd13e768a40ccbb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5237020


Reviewed-by: Adenilson Cavalcanti <cavalcantii@chromium.org>
Commit-Queue: Hans Wennborg <hans@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1253252}
NOKEYCHECK=True
GitOrigin-RevId: 2f39ac8d0a414dd65c0e1d5aae38c8f97aa06ae9