[liblsl] Fix installation

[ehsan-mohammadi]

In the previous PR (#7906), I changed add_excutable to add_library with a patch file to remove .exe files and avoid build failures. But this is a wrong way. So I fixed it in this PR.

[ehsan-mohammadi]

@cbezault @cenit Can you please check this PR?

[cbezault]

Yeah this looks right, though why only on WIN32? Is the port only buildable on a windows host? If it has to do with the target as opposed to the host (though right now I see that this port is only getting built on Windows) you should use VCPKG_TARGET_IS_WINDOWS.

[ehsan-mohammadi]

@cbezault I thought liblsl buildable on Linux and OSx too. So, do you think it getting built only on Windows? And should I change if(WIN32) to if(VCPKG_TARGET_IS_WINDOWS)?

[Rastaban]

Yes, change the line to if(VCPKG_TARGET_IS_WINDOWS)

liblsl may be build able on Linux and OSX, but it is currently marked as not supported in our CI system. I have attached the failure build log if you are curious. install-x64-linux-dbg-out.log

[ehsan-mohammadi]

@Rastaban Thanks for helping me. I'll do it.