Fails to compile on android: NULL used in arithmetic

I downloaded the recent ZeroMQ release 3.2.2 (from 2012/11/23) and it fails to compile for android with the ndk8:

$ make
Making all in src
make all-am
CXX libzmq_la-address.lo
CXX libzmq_la-clock.lo
CXX libzmq_la-ctx.lo
CXX libzmq_la-decoder.lo
cc1plus: warnings being treated as errors
In file included from decoder.cpp:31:
decoder.hpp: In member function 'bool zmq::decoder_base_t<T>::stalled() [with T = zmq::decoder_t]':
decoder.cpp:166: instantiated from here
decoder.hpp:152: error: NULL used in arithmetic
make[2]: *** [libzmq_la-decoder.lo] Error 1
make[1]: *** [all] Error 2
make: *** [all-recursive] Error 1

I followed the guide at [1] and tried both the 3.2.2 release and a clone of the zeromq3-x repository, both will fail to compile with the above error message.

Best regards
Stefan

[1] http://www.zeromq.org/build:android