PFS: unblock the child when unsuspending an accept

Previously, PFS would incorrectly try to unsuspend the parent (i.e.,
the listening socket), resulting in the child hanging until the other
side performed another action. Test56 started failing on this now.

Change-Id: I231ac5481c83ac45951d33aeecc8149273f48b11
increase -Werror resilience

for bin/, commands/, libexec/, sbin/, test/, usr.bin/ and usr.sbin/.

Change-Id: I8fa12c3cd86865311cef71b7faa7cf4fa785174f