[Bug libstdc++/60407] call of overloaded ‘isnan’ is ambiguous

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60407

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This sounds like you are including math.h and then later on cmath.  I don't
know if this is a valid thing to do.