rem: modname = resolve_env(*a, phase, 1, names, NULL);
add: modname = resolve_env(*a, phase, 1, names, scheme_null);
context: Scheme_Object *scheme_stx_module_name(Scheme_Object **a, long phase, 				      Scheme_Object **nominal_modidx,				      Scheme_Object **nominal_name,				      int *mod_phase)     /* If module bound, result is module idx, and a is set to source name.	If lexically bound, result is scheme_undefined and a is unchanged. 	If neither, result is NULL and a is unchanged. */{  if (SCHEME_STXP(*a)) {    Scheme_Object *modname, *names[4];    names[0] = NULL;    names[3] = scheme_make_integer(0);    modname = resolve_env(*a, phase, 1, names, NULL);        if (names[0]) {      if (SAME_OBJ(names[0], scheme_undefined)) {	return scheme_undefined;      } else {	*a = names[0];	if (nominal_modidx)	  *nominal_modidx = names[1];	if (nominal_name)	  *nominal_name = names[2];	if (mod_phase)	  *mod_phase = SCHEME_INT_VAL(names[3]);	return modname;      }    } else      return NULL;  } else    return NULL;}