Returns the complex conjugate of its argument.
    This function is supported on OpenVMS Integrity servers and
    Alpha only.
    Format
      #include  <complex.h>
      double complex conj  (double complex z);
      float complex conjf  (float complex z);
      long double complex conjl  (long double complex z);
1 – Argument
 z
    A complex value.
2 – Description
    The conj functions return the complex conjugate of z, by
    reversing the sign of its imaginary part.
3 – Return Values
x The complex conjugate value.