Add more readable name for isnan() from math.h [imported]

[cmaglie]

This is Issue 812 moved from a Google Code project. Added by 2012-02-10T18:03:34.000Z by [email protected]. Please review that bug for more context and additional comments, but update this bug.

Original labels: Type-Enhancement, Priority-Medium, Component-Core

Original description

There are some useful functions in math.h, especially isnan(). We should add a few defines to give them more beginner-readable names.