SVR4 and other systems provide a header file named "nan.h" which defines
macros and constants such that an application can determine if a given
floating point number is NaN (not a number).  NetBSD lacks this file, but
I am trying to port an application which uses one of its defined macros,
namely ``IsNANorINF()''.  (Returns true if the supplied argument is NaN or
infinity.)

What the correct way to do the above in NetBSD?

-J