[lmi] Do we have zlib already?

[Greg Chicares]

I just built wx, and I see:
|  Which libraries should wxWidgets use?
...
|    zlib               sys
Does that mean we already have zlib? (I don't imagine that "sys"
here could mean that the Cygwin zlib is used, because that would
depend on an entirely different C RTL.)

Elsewhere in my log I see:

rm -f 
/opt/lmi/wx-scratch/wxWidgets-c4d06e8.../gcc-491-97e6a75.../lib/libwxzlib-3.1-i686-w64-mingw32.a

so it looks like 'make clean' attempts to remove a 'libwxzlib'
library that perhaps wx knows how to build.

Here's why I ask. We've been distributing product files as plain
xml. They contain proprietary product data (no personal data),
with an appropriate notice at the top, and they're distributed
only under nondisclosure agreements. Now at least one person has
suggested that it would be even better if they weren't readily
human-readable, so I was thinking that compressing them with
zlib might be a good idea. AFAICT, libxml2 and thus xmlwrapp use
zlib transparently if it's available. And if we already have
zlib (e.g. because wx knows how to build it), this might be an
easy enhancement.