message: Specify AM_CPPFLAGS for ZMQ.
  When building the ZMQ static library, add AM_CPPFLAGS to the library
  CPPFLAGS.  Otherwise, we may miss important flags that are specified
  elsewhere.  For instance, if --enable-debug is passed and
  DDEBUG_LOCKORDER set, then that would not apply to the ZMQ library
  before (causing potential for hard-to-find bugs).
diff: @@ -309,7 +309,7 @@ libbitcoin_server_a_SOURCES += dummywallet.cpp
  endif
  if ENABLE_ZMQ
  -libbitcoin_zmq_a_CPPFLAGS = $(BITCOIN_INCLUDES) $(ZMQ_CFLAGS)
  +libbitcoin_zmq_a_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) $(ZMQ_CFLAGS)
  libbitcoin_zmq_a_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
  libbitcoin_zmq_a_SOURCES = \
  zmq/zmqabstractnotifier.cpp \
  