[feature] Export DLL functions to a .lib for dynamic linking

[uilianries]

Hello!

As we continue to package this project in Conan (conan-io/conan-center-index#27532), a scenario that our CI runs is Windows, and it builds the library as both static and shared.

However, when building as shared, it fails because the project doesn't export functions via __declspec, so only the DLL is provided. As a result, consumers will need to use the LoadLibrary Windows API and load each method manually.

You can see the build result and log here:

• https://github.com/conan-io/conan-center-index/pull/27532/checks?check_run_id=58526101113
• https://c3i.jfrog.io/artifactory/cci-build-logs/cci/prod/PR-27532/3/package_build_logs/build_log_lifthttp_4_4_2_5fd301695e1b28b5c4e847371199f56e_7d2dda0dbe3787826bb096a89e82463d8b6c729d.success.txt

It would be great in the future to have it supported as well; it will have a much smoother integration for Windows usage, for example. CMake provides a native feature like WINDOWS_EXPORT_ALL_SYMBOLS, but it's usually not recommended, because it exports even private symbols, which may causing brekage to users who are consuming what should be private.

For extra context about DLLs, you can read the official Microsoft documentation: https://learn.microsoft.com/en-us/troubleshoot/windows-client/setup-upgrade-and-drivers/dynamic-link-library#load-time-dynamic-linking

Regards!

[laci-aura]

Hello,
it looks like not so many people are using the library on Windows (if any). I'd suggest adding WINDOWS_EXPORT_ALL_SYMBOLS to make it more usable in the first place

[jbaldwin]

I've wanted to add windows as a first class platform for a while, see #166, but I don't really have a great way of getting this working myself. If you would be interested in getting a ci-windows.yml working I think that would be awesome and a great first point. I'd then suggest starting with WINDOWS_EXPORT_ALL_SYMBOLS get it working, and then if a cleaner solution with actual exports in the code could make sense as a final follow up I would support that.