[clang] [Clang][SYCL] Introduce clang-sycl-link-wrapper to link SYCL offloading device code (Part 1 of many) (PR #112245)

[Chris B via cfe-commits]

https://github.com/llvm-beanz commented:

At a minimum I think this change needs more tests. There's a lot of code added with very minimal test coverage.

I'm uncomfortable with adding a design that is effectively a workaround with an unwritten "TODO" to fix it up later, but I also don't want to needlessly block things.

>From the discourse post and everything I've found reading about the SYCL tooling, it seems to me like this should really just all be integrated into LLD and performed with the linking phase. It seems like a huge waste of IO to read objects, rip out device-specific bits, process that separately, then read the objects again in another process to link the host bits, then in a third process read the linked host and device bits and combine them... 

https://github.com/llvm/llvm-project/pull/112245