diff --git a/src/libstrongswan/plugins/keychain/Makefile.am b/src/libstrongswan/plugins/keychain/Makefile.am
index 508a4b024..bd04db33d 100644
--- a/src/libstrongswan/plugins/keychain/Makefile.am
+++ b/src/libstrongswan/plugins/keychain/Makefile.am
@@ -1,5 +1,5 @@
 
-INCLUDES = -I$(top_srcdir)/src/libstrongswan
+AM_CPPFLAGS = -I$(top_srcdir)/src/libstrongswan
 
 AM_CFLAGS = -rdynamic