(CHK_CONNECTION): Use the "do ... while (0)" construct to make
	this macro expand to exactly one statement.
(CHK_LOGIN): Ditto.
(CONF_ZERO): Ditto.
(CHK_EXIST): Ditto.
(GET_P_STAT): Ditto.
(VOID_GET_P_STAT): Ditto.
(GET_C_STAT): Ditto.
(VOID_GET_C_STAT): Ditto.
(GET_T_STAT): Ditto.
(VOID_GET_T_STAT): Ditto.