Fix GH-9493: fix ancillary data build for FreeBSD prior to the 13 release.

the legacy sockcred struct does not hold the process id, thus sockcred2
 had been added from FreeBSD 13 in conjunction with LOCAL_CREDS_PERSISTENT
 to address this thus we disable the feature for earlier releases.

Author: devnexen

ext/sockets/conversions.h

@@ -8,6 +8,13 @@
 # include <sys/socket.h>
 # if defined(__FreeBSD__) || defined(__NetBSD__)
 #  include <sys/un.h>
+#  if defined(__FreeBSD__)
+     // we can't fully implement the ancillary data feature with
+     // the legacy sockcred/LOCAL_CREDS (due to lack of process
+     // id handling) do we disable it since only
+     // sockcred2/LOCAL_CREDS_PERSISTENT can address it.
+#    undef LOCAL_CREDS
+#  endif
 # endif
 #else
 # include <Ws2tcpip.h>