Adjust to the moving target called the C++ standard. Apparently nowadays it's not allowed to define an explicit copy constructor but not an assignment operator. Consequently, defining the explicit copy constructor in terms of the implicit/automatic assignment operator for general convenience no longer works. Add assignment operators. Caution: not tested with the IBM compiler, but there's no particular reason it shouldn't work.

... illegal redefinitions
#define ZERO (1-1)
#define ZERO (1 - 1)
#define IDENTITY(x)  ( x )
#define IDENTITY(y)  ( y )
#define IDENTITY(x)  ( y )