-SUBDIRS = demo spamassassin
+if BUILD_DEMO_PLUGIN
+demo_dir = demo
+endif
+
+if BUILD_SPAMASSASSIN_PLUGIN
+spamassasssin_dir = spamassassin
+endif
+
+if BUILD_MATHML_VIEWER_PLUGIN
+mathml_viewer_dir = mathml_viewer
+endif
+
+if BUILD_DILLO_VIEWER_PLUGIN
+dillo_viewer_dir = dillo_viewer
+endif
+
+
+SUBDIRS = $(demo_dir) $(spamassasssin_dir) $(mathml_viewer_dir) \
+ $(dillo_viewer_dir)