[CVE] zlib (< 1.2.12) memory corruption

[Nick Clifton]

Hi Luis,

> There is a CVE [1] for zlib < 1.2.12 (released march 27th).
> 
> GCC currently uses zlib 1.2.11, and binutils-gdb imports the zlib directory from GCC. The recommendation is to get it updated to 1.2.12, which contains the proper fix [2].
> 

Right - I have now updated the binutils-gdb mainline sources with this release.

Whilst it is true that the gcc version of zlib sources had diverged slightly from
the 1.2.11 release sources, I think that it was just some changes cherry picked
from the developments that went in to 1.2.12.  So a simple rebase should be safe.

Cheers
   Nick