ngircd: Disable "tcp wrappers", not available on OS X 10.8

Starting OS X 10.8, the "tcp wrappers" library is no longer part of
the operating system, so don't use it any more.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
ngircd 20.1

Closes #16909.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>