rem: if (username == 0)
add: if (!username)
context: xgetgroups (const char *username, gid_t gid, int *n_groups,	    GETGROUPS_T **groups){  int max_n_groups;  int ng;  GETGROUPS_T *g;  int fail = 0;  if (username == 0)    max_n_groups = getgroups (0, NULL);  else    max_n_groups = getugroups (0, NULL, username, gid);  /* Add 1 just in case max_n_groups is zero.  */  g = (GETGROUPS_T *) xmalloc (max_n_groups * sizeof (GETGROUPS_T) + 1);  if (username == 0)    ng = getgroups (max_n_groups, g);  else    ng = getugroups (max_n_groups, g, username, gid);  if (ng < 0)    {      error (0, errno, _("cannot get supplemental group list"));      ++fail;      free (groups);    }  if (!fail)    {      *n_groups = ng;      *groups = g;    }  return fail;}