The convention is not to check the prefix before `error: `.
This gives flexibility if we need to rename ld64.lld to something else,
(e.g. a while ago we used ld64.lld.darwinnew).
There was an instance of a third-party archive containing multiple
_llvm symbols from different files that clashed with each other
producing duplicate symbols. Symbols under the LLVM segment
don't seem to be producing any meaningful value, so just ignore them.
Reviewed By: #lld-macho, int3
Differential Revision: https://reviews.llvm.org/D108016