Merge pull request #475 from compnerd/chasing-my-tail

shims: correct `TAILQ_CONCAT`

Author: ktopley-apple

src/shims/generic_sys_queue.h

@@ -95,7 +95,7 @@
 #define TAILQ_CONCAT(head1, head2, field) do { \
 if (!TAILQ_EMPTY(head2)) { \
 (head1)->tq_last = (head2)->tq_first; \
-(head1)->tq_first->field.te_prev = (head1)->tq_last; \
+(head2)->tq_first->field.te_prev = (head1)->tq_last; \
 (head1)->tq_last = (head2)->tq_last; \
 TAILQ_INIT((head2)); \
 } \