V3 PATCH: #undef some C99 math macros in <cmath>

[Gabriel Dos Reis]

Jason Merrill <jason_merrill@redhat.com> writes:

| I don't see why putting these functions (apart from clog) in std would be a
| problem; they use names that are not otherwise defined in std, and
| therefore can not be detected by a conforming program.

But aren't we also required to diagnose programs using extensions? ;-)

In my opnion creating a separate namespace std::iso_c99 makes it
easier to deal with binary compatibility issues latter in case the
committee makes  any conflicting decisions.

-- Gaby