Fix Windows dependency library names

[hughbe]

• CMark is called cmark.lib on Windows
• Clang is called libClang*.lib on Windows

[compnerd]

This is rather unfortunate that we need to do this. I don't see a better way though.

[compnerd]

CC @llvm-beanz in case you see a better way (other than re-architecting the cross-compilation)

[compnerd]

@swift-ci please test and merge

[compnerd]

@swift-ci please test and merge

[compnerd]

@swift-ci please test linux platform

[llvm-beanz]

I have a really crazy idea that we might be able to use to make some of this stuff simpler. It would be very non-traditional CMake, but it might make this world better in the short term.

Long term, as I've said before, Swift needs to stop fighting with CMake's cross-compilation strategy.

Short term, I think we might be able to streamline some of the platform handling goop with a few convenience wrappers. But we'd have to be careful to do it only in places where the platform-handling code can be placed in its own scope.

What I'm thinking here is that we could do something like:

if("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "WINDOWS") include(Windows) else() include(UNIX) endif() set(dep "${LLVM_LIBRARY_OUTPUT_INTDIR}/${dep}.${CMAKE_STATIC_LIBRARY_SUFFIX}")

I believe that doing this in an isolated scope (inside a function) should be safe, and it would allow for more generic code.

We could even abstract the if block into a macro for re-use.