TLFLAGS_IN_TDLIST
curthread->tlflags &= ~TLFLAGS_IN_TDLIST;
if (((thrd)->tlflags & TLFLAGS_IN_TDLIST) == 0) { \
(thrd)->tlflags |= TLFLAGS_IN_TDLIST; \
if (((thrd)->tlflags & TLFLAGS_IN_TDLIST) != 0) { \
(thrd)->tlflags &= ~TLFLAGS_IN_TDLIST; \