MAX and MIN intrinsics with REAL NaN arguments

The Fortran standard does not specify what the result of the MAX and MIN intrinsics are if one of the arguments is a NaN. Accordingly, the GNU Fortran compiler does not specify that either, as this allows for faster and more compact code to be generated. If the programmer wishes to take some specific action in case one of the arguments is a NaN, it is necessary to explicitly test the arguments before calling MAX or MIN, e.g. with the IEEE_IS_NAN function from the intrinsic module IEEE_ARITHMETIC.