diff --git a/src/Makefile.am b/src/Makefile.am
index 6d10f86d57..19b131a5f4 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -710,6 +710,7 @@ libbitcoin_util_a_SOURCES = \
   $(BITCOIN_CORE_H)
 
 if USE_LIBEVENT
+libbitcoin_util_a_CPPFLAGS += $(EVENT_CFLAGS)
 libbitcoin_util_a_SOURCES += util/url.cpp
 endif
 #