The logic for strsignal and strerror is very similar, so I've moved them
both to use a shared utility (MessageMapper) for the basic
functionality.
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D135322
I've implemente the gnu variant of strerror_r since that seems to be the
one more relevant to what we're trying to do.
Differential Revision: https://reviews.llvm.org/D135227
Strerror maps error numbers to strings. Additionally, a utility for
mapping errors to strings was added so that it could be reused for
perror and similar.
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D134074