[lld] [LLD] [MinGW] Ignore the -rpath option (PR #102886)

[Martin Storsjö via llvm-commits]

mstorsjo wrote:

> Since this option isn't supposed to work with Windows, maybe it can emit a warning? (Not blocking. Honestly, either way seems fine.)

Hmm, I think that sounds like a good idea! The number of users running into this option seems moderately low anyway (but nonzero), so that would probably help pushing things towards getting rid of it.

I was pondering if this change could be backport worthy (even though we're getting towards RC3) because it's so trivial (and should be near zero risk) - but if we'd extend it with a warning, it's slightly less of a trivial thing and maybe less backportable. So in that case it's probably better to not backport it and just wait for 20.x...

https://github.com/llvm/llvm-project/pull/102886