Use system zlib instead of bundled.

[Nakhr11n]

It's unnecessary to keep zlib in the project files.
Better to link against system zlib, which is probably more up to date.

If we really want to link statically, I would suggest using CMake ExternalProject to do so.

[Lgt2x]

CI scripts and build instructions will need updated to install zlib

[Nakhr11n]

CI and build instructions updated.

[winterheart]

Better to use vcpkg to install required dependencies. It has native cmake integration via toolchain files and can build zlib statically on request.

[Nakhr11n]

Forgot about Mac and Windows.
They work now.

[Nakhr11n]

Now the vcpkg issues are resolved. In github actions the vcpkg path is hardcoded since the VCPKG_ROOT envvar isn't set. Otherwise it uses VCPKG_ROOT.

[Lgt2x]

I'm being nit-picky here but could you please update README build instructions for Windows users to include VCPKG please ? @Arcnor can confirm but after that I think we're ready to merge :)

[Arcnor]

Yeah, it will be great, because this PR introduced extra steps to build the project.

You can just mention the need to define VCPKG_ROOT before calling the CMake commands.

[Nakhr11n]

Now there is no more extra github actions step, vcpkg has been included in the readme.

[Arcnor]

Thanks @Nakhr11n and sorry for all the requests, if you fix the conflict we can just merge this :)

[Nakhr11n]

Conflicts fixed. Thank you for the feedback :)