Computes (x * y) + z, rounded as one ternary operation.
    This function is OpenVMS Alpha and Integrity servers only.
    Format
      #include  <math.h>
      double fma  (double x, double y, double z);
      float fmaf  (float x, float y, float z);
      long double fmal  (long double x, long double y, long double z);
1 – Argument
 x,y,z
    Real values.
2 – Description
    The fma functions compute (x * y) + z, rounded as one ternary
    operation: the value is computed as if to infinite precision and
    rounded once to the result format, according to the rounding mode
    characterized by the value of FLT_ROUNDS.
3 – Return Values
    n                  Upon success, (x * y) + z, rounded as one
                       ternary operation.
    NaN                x or y is NaN; errno is set to EDOM.