Missing "defined" tokens added

The missing tokens broke the build if you used -Werror -Wundef
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

src/tcp_address.cpp

@@ -110,7 +110,7 @@ int zmq::tcp_address_t::resolve_nic_name (const char *nic_, bool ipv4only_)
     return 0;
 }
 
-#elif defined ZMQ_HAVE_AIX || ZMQ_HAVE_HPUX || ZMQ_HAVE_ANDROID
+#elif defined ZMQ_HAVE_AIX || defined ZMQ_HAVE_HPUX || defined ZMQ_HAVE_ANDROID
 
 #include <sys/types.h>
 #include <unistd.h>