Teaching Neon to compile ZLib on Windows

[Branko Čibej <br...@xbc.nu>]

Hi!

The other day while compiling Subversion on Windows in debug mode, I got 
fed up with warnings about how ZLib wasn't linked against the debug CRT. 
So I decided that it was time to revamp Neon's Win32 makefile again so 
that it compiles ZLib with the correct parameters. Since ZLib 1.2.1 
includes an acceptable makefile, and has been around for quite a while, 
I thought that requiring this version (on Windows only) would not be too 
ornery.

The patch is attached, diffed against the 0.24.x branch.

[[[
Change the Win32 build to compile ZLib from sources, and change the ZLib
versin requirement. This doesn't change neon.mak's external interface.

* neon.mak: Add parameters and targets for building ZLib from source.
* INSTALL.win32: Update the documentation, and note that the ZLib version
  must be at least 1.2.1.
]]]


-- Brane