Describe the bug
It is surprisingly difficult to build curl on Windows without the default non-http feature.

• "vcpkg.exe install curl" installs curl[core,non-http,schannel,ssl,sspi,winssl], due to "non-http" being default. Fine so far.
• "vcpkg.exe install curl[core,ssl]" also installs the non-http feature, which is a bit surprising, because I explicitly want to disable it.
• "vcpkg.exe install curl[core,schannel]" installs curl[core,schannel,sspi], which is what I want.

I think the problem comes from the feature mapping ssl -> winssl -> schannel -> sspi, where only the latter two actually enter the CMake build. The feature winssl does not reference curl[core,schannel], but curl[schannel] (or, in the latest version, does not set default-features to false).

Since this behavior is different from Linux, I guess it counts as a bug.