XSIMPLEQ_XOR
#define XSIMPLEQ_FIRST(head) XSIMPLEQ_XOR(head, ((head)->sqx_first))
#define XSIMPLEQ_NEXT(head, elm, field) XSIMPLEQ_XOR(head, ((elm)->field.sqx_next))
(head)->sqx_first = XSIMPLEQ_XOR(head, NULL); \
(head)->sqx_last = XSIMPLEQ_XOR(head, &(head)->sqx_first); \
XSIMPLEQ_XOR(head, NULL)) \
(head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \
(head)->sqx_first = XSIMPLEQ_XOR(head, (elm)); \
(elm)->field.sqx_next = XSIMPLEQ_XOR(head, NULL); \
*(XSIMPLEQ_XOR(head, (head)->sqx_last)) = XSIMPLEQ_XOR(head, (elm)); \
(head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \
XSIMPLEQ_XOR(head, NULL)) \
(head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \
(listelm)->field.sqx_next = XSIMPLEQ_XOR(head, (elm)); \
if (((head)->sqx_first = XSIMPLEQ_XOR(head, \
(head)->sqx_first)->field.sqx_next) == XSIMPLEQ_XOR(head, NULL)) \
(head)->sqx_last = XSIMPLEQ_XOR(head, &(head)->sqx_first); \
if (((elm)->field.sqx_next = XSIMPLEQ_XOR(head, \
== XSIMPLEQ_XOR(head, NULL)) \
XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \