"samba -b" reports the following: WINBINDD_PRIVILEGED_SOCKET_DIR: /usr/local/samba/var/lib/winbindd_privileged In fact, the default install goes to "/usr/local/samba/var/locks/winbindd_privileged". Even if you choose a different path at configure time, the reported path is always that same.
Even when explicitly configuring with --with-privileged-socket-dir=/usr/local/samba/var/lib the final path still is "${LOCALSTATEDIR}/winbindd_privileged" instead of "${LOCALSTATEDIR}/lib/winbindd_privileged". Looks like the install path is hard-coded somewhere and does not reflect the configuration option.