Upstream libffi port fixes

[qmfrederik]

To remove this workaround:

• https://github.com/qmfrederik/tools-vcpkg/commit/3b3bf4ab72a0ad458b6c409e2b3cc2ec6ee26848
• https://github.com/qmfrederik/tools-vcpkg/commit/87acb04245dd37864e34364f81909a7003ba7f56

[qmfrederik]

• Building as a shared library fails because it tries to link with luuid and loldnames -- see https://github.com/microsoft/vcpkg/pull/40936
• After that, linking fails because it tries to invoke clang with a cl syntax (e.g. -EXPORT:{symbol}), so workaround for now can be to build using clang-cl instead