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 "utils.h"

void *domalloc(size_t len) {
  void *x = malloc(len);
  if (!x) {
    fprintf(stderr, "Out of memory\n");
    exit(1);
  }
  return x;
}

char *dostrdup(const char *s) {
  char *x = strdup(s);
  if (!x) {
    fprintf(stderr, "Out of memory\n");
    exit(1);
  }
  return x;
}