[Bug c/87488] hyperlink filenames in diagnostics

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87488

--- Comment #14 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Thanks.

systemd also uses '\a':
  https://github.com/systemd/systemd/blob/master/src/shared/pretty-print.c#L53
    n = strjoin("\x1B]8;;", url, "\a", text, "\x1B]8;;\a");

I didn't see your update to this BZ after our discussion on IRC, and
independently came up with the same patch as your one in comment #13, so I
think that's the right approach.

Shall I go ahead and bootstrap/test/commit the patch, or do you want to?