[Bug testsuite/80557] New: rewrite absolute line numbers into relative or saved line numbers

["vries at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80557

            Bug ID: 80557
           Summary: rewrite absolute line numbers into relative or saved
                    line numbers
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: trivial
          Priority: P3
         Component: testsuite
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vries at gcc dot gnu.org
  Target Milestone: ---

https://gcc.gnu.org/ml/gcc-patches/2017-04/msg01280.html:
...
Are there any spots where the relative line number is with too big bias
(say .+10 or .-10 and more)?  I guess those should be decided case by case
whether we want relative, absolute or saved line numbers.  If the
diagnostic is within the same function or code block as the stuff it is
relative to, relative is fine, but if e.g. the messages are just at the end
of file and there are unrelated functions in between, it is not a good idea
to use relative.
...