[CMake] Finding Zlib on Windows

[Alexander Neundorf]

On Thursday 11 September 2008, Leo Breebaart wrote:
> I am having a heck of a time correctly detecting Zlib (and other
> libraries) properly on Windows.
>
> Being a newcomer to both CMake and the wonderful world of Windows
> .dll and .lib files I fully expect that I am getting things wrong
> left and right, and I am hoping people here are willing to help a
> newbie along.
>
> The goal:
>
> I want to build a library that itself depends on Zlib, and I want
> to build this library in both shared and static variants.
>
> The Zlib I want to use is a self-compiled version of the standard
> www.zlib.net v1.2.3 release, and it can be located anywhere on
> the system.
>
> I would like to keep my solution as generic as I can, and not
> just hardcode paths that work on *my* setup.
>
>
> The problems:
>
> (1) On Windows, FindPackage(ZLIB) does not work because Zlib can
> be anywhere. So I wrote the following CMakeLists fragment in
> order to either accept a ZLIB_DIR location from the cmake command
> line, or from an environment variable, and use that to tweak the
> paths for FindPackage:

I would recommend not to add environment variables for that.
With cmake >= 2.6.0 you can set CMAKE_PREFIX_PATH to a list of custom 
directories where cmake should search. Add the install location of your zlib 
to it, then it should work.
I would also suggest not to use a dll/ subdir. 
Just go with lib/.
Then you also don't have to modify CMAKE_INCLUDE_PATH  and CMAKE_LIBRARY_PATH 
anymore.

Alex