Even though it doesn't make sense, there seems to be multiple programs
in the wild that create PC-relative relocations in non-ALLOC sections.
This is caused by the negligence of GNU linkers to not report any errors
for such relocations.
Currently, lld emits warnings against such relocations and exits.
So, you cannot link any program that contains wrong relocations until
you fix an issue in a program that generates wrong ELF files. It's often
impractical because it isn't always easy to fix a problem in a ELF-
generating program.
This patch relaxes the error checking and emit a warning instead.