zlib: split up to match original source tree

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>
diff --git a/lib/zlib/zlib.h b/lib/zlib/zlib.h
new file mode 100644
index 0000000..556be32
--- /dev/null
+++ b/lib/zlib/zlib.h
@@ -0,0 +1,20 @@
+/* Glue between u-boot and upstream zlib */
+#ifndef __GLUE_ZLIB_H__
+#define __GLUE_ZLIB_H__
+
+#include <common.h>
+#include <compiler.h>
+#include <asm/unaligned.h>
+#include <watchdog.h>
+#include "u-boot/zlib.h"
+
+/* avoid conflicts */
+#undef OFF
+#undef ASMINF
+#undef POSTINC
+#undef NO_GZIP
+#define GUNZIP
+#undef STDC
+#undef NO_ERRNO_H
+
+#endif