[lld] [lld][wasm] Allow stub libraries to depend on optional linker symbols (PR #215112)

[Gauarv Chaudhary via llvm-commits]

ANAMASGARD wrote:

Sir @sbc100  I haven't personally encountered this in one of my own projects. I came across the existing issue while looking into wasm-ld issues, reproduced the failure locally, and worked on fixing it.

So I don't have a downstream project that would be directly unblocked by this change. My motivation was fixing the existing linker correctness issue rather than a personal real-world dependency.

https://github.com/llvm/llvm-project/pull/215112