Could LLVMConfig.cmake export the LLVM_USE_CRT_* fields?

Hey all,

It'd be super useful for us if we could export any LLVM_USE_CRT_* fields that were set by a user into the LLVMConfig.cmake that goes into an LLVM install.

This will enable us to pick up the same CRT in some of our projects that bring in a previously installed LLVM, solving some gnarly linker errors for our users.

Anyone got any objections to this before I propose a patch?

Cheers,
-Codeplay Neil.