Commit 340fdf1303dc ("zlib: Port fix for CVE-2016-9841 to U-Boot")
brings a big performance regression in inflate_fast(), which leads
to watchdog timer reset on powerpc 8xx.

It looks like that commit does more than what it describe, it
especially removed an important optimisation that was doing copies
using halfwords instead of bytes. That unexpected change multiplied
by almost 4 the time spent in inflate_fast() and increased by 40%
the overall time needed to uncompress linux kernel image.

So partially revert that commit but keep post incrementation as it
is the initial purpose of said commit.

[trini: Combine assorted patches in to this one, just restoring the
        performance commit]

Fixes: 340fdf1303dc ("zlib: Port fix for CVE-2016-9841 to U-Boot")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Tom Rini <trini@konsulko.com>

In order to make it easier to move on to dropping common.h from code
directly, remove common.h inclusion from the rest of the header file
which had been including it.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>

Including <linux/compiler.h> is enough for general use.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

While looking to upgrade to zlib-1.2.5, the current mondo merge of
multiple files into a single was making things way more difficult
than it should have been.  Hard to pick out what has been changed
to port it to U-Boot, been removed as useless, and bug fixes added
after the fact.

So split the single file up into the original file names, and merge
non-essential changes back from the original tree (for some reason,
style in code in a bunch of places was changed to U-Boot style even
though this isn't "U-Boot" code).

The original build style is retained -- we have a single zlib.c that
includes all the other files, and that is the only file we compile.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>