[lld] [ELF] Add --compress-section to compress matched non-SHF_ALLOC sections (PR #84855)

[Roland McGrath via llvm-commits]

frobtech wrote:

I think the only concern about the "warn for SHF_ALLOC match" behavior is if someone wanted to use a catch-all (or otherwise very wide) pattern with the expectation of it omitting SHF_ALLOC sections whose names match. But I think that's a new outlying use that we can address in later iterations. The warning behavior seems like a conservative and safe way to add the feature initially.

https://github.com/llvm/llvm-project/pull/84855