Multiline error and warning messages in the libstdc++ testsuite

[Gabriel Dos Reis]

"Billinghurst, David (CRTS)" <David.Billinghurst@riotinto.com> writes:

| Multiline error and warning messages from g++ confuse the libstdc++-v3
| testsuite.  This is worked around with "excess error" tests.  See, for
| example, 23_containers/set_operators.cc and the discussion in
| libstdc++/5145 and libstdc++/5146.
| 
| The error processing is done in procedure dg-test, which is part of
| dejagnu.  Rather than change this it seemed simpler to unwrap the
| multi-line messages, converting them back to single lines of text.

Please, don't do that. The correct way is to set -fmessage-length=0 on
the command line.

-- Gaby