update zlib to 1.2.8

[Jeff Law]

On 11/22/2015 09:37 PM, Matthias Klose wrote:
> In GCC zlib is only used for libjava; for binutils and gdb it is used
> when building without --with-system-zlib.  This just updates zlib from
> 1.2.7 to 1.2.8 (released in 2013).  Applies cleanly, libjava still
> builds and doesn't show any regressions in the testsuite.  Ok to apply
> (even if we already are in stage3)?
>
> Matthias
>
> zlib/ChangeLog.gcj
>
> +2015-11-23  Matthias Klose  <doko@ubuntu.com>
> +
> +       * Imported zlib 1.2.8; merged local changes.
OK, though it's really late for this.  My biggest worry here given GCJ's 
status is build failures on the lesser used hosts.   If it causes 
significant problems we'll have to revert.

Jeff