rem: return grp ? xstrdup (grp->gr_name) : uint_to_string (gid);
add: return xstrdup (grp ? grp->gr_name : TYPE_SIGNED (gid_t) ? imaxtostr (gid, buf) : umaxtostr (gid, buf));
context: gid_to_name (gid_t gid){  struct group *grp = getgrgid (gid);  return grp ? xstrdup (grp->gr_name) : uint_to_string (gid);}