diff --git a/src/Makefile.am b/src/Makefile.am
index 54743878..ff3d51ef 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -240,7 +240,7 @@ libbitcoin_server_a_SOURCES = \
 if ENABLE_ZMQ
 LIBBITCOIN_ZMQ=libbitcoin_zmq.a
 
-libbitcoin_zmq_a_CPPFLAGS = $(BITCOIN_INCLUDES)
+libbitcoin_zmq_a_CPPFLAGS = $(BITCOIN_INCLUDES) $(ZMQ_CFLAGS)
 libbitcoin_zmq_a_SOURCES = \
   zmq/zmqabstractnotifier.cpp \
   zmq/zmqnotificationinterface.cpp \