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.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "topic.h"
#include "helpgen.h"

void htmlout(const char *file, struct topic **topics, int ntopics) {
  // XXX
  (void)file;
  (void)topics;
  (void)ntopics;
  fprintf(stderr, "Can't do html output yet\n");
  exit(1);
}