[Dune] Flyspray 956, DUNE_DEPRECATED, and compiler support

[Bård Skaflestad]

Dear Dune,

Christian mentioned earlier today that

    __attribute__((deprecated(msg))

might not be supported in all compilers.  As far as I can tell from a
cursory reading of the GCC manuals at gcc.gnu.org, "deprecated(msg)" was
not introduced until the relatively recent 4.5.x release series.


Sincerely,
-- 
Bård Skaflestad <Bard.Skaflestad at sintef.no>
SINTEF ICT, Applied Mathematics