Avoid 'internal_state' macro pollution from zlib.h.

This ends up conflicting with use of 'internal_state' as a member function
name in mojo header files. It creates problems especially with jumbo builds.
Fixing it here rather than just working around it in the jumbo build helps
avoid others from stumbling over this in the future (especially as we start
utilizing mojo more).

Change-Id: I649fd80eb80c57e445b78819e9dc674adbf901bd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1709871


Commit-Queue: Darin Fisher <darin@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#679268}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: c56fa983a92c26a87fdf36027cc03a19edd9c157