diff --git a/src/libstrongswan/Makefile.am b/src/libstrongswan/Makefile.am
index 1b7fbc358..351e79913 100644
--- a/src/libstrongswan/Makefile.am
+++ b/src/libstrongswan/Makefile.am
@@ -116,7 +116,11 @@ $(srcdir)/crypto/proposal/proposal_keywords.c:	$(srcdir)/crypto/proposal/proposa
 # build plugins with their own Makefile
 #######################################
 
+if MONOLITHIC
 SUBDIRS =
+else
+SUBDIRS = .
+endif
 
 if USE_AES
   SUBDIRS += plugins/aes