set FD_CLOEXEC on dmn pipes just in case
use logf_errno() instead of strerror
get rid of threads_cleanup stuff

I don't think these do any useful debugging anyways
ignore clang analyzer outputs
remove excess space from prefix strings
fix memleak in ztree_destroy_clone()
fix "leak" of zscan_t in zscan_djb
fix various leaks of deleted zone_t in zsrc_djb
Merge branch '2.x' into dmn-rework