diff --git a/src/Makefile.am b/src/Makefile.am
index c4d3f767..0ffe7cfe 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -74,6 +74,7 @@ noinst_HEADERS = \
 	request_body_processor/*.h \
 	utils/*.h \
 	variables/*.h \
+	engine/*.h \
 	*.h