--- a/make/Javadoc.gmk	Wed Nov 23 16:16:33 2016 +0000
+++ b/make/Javadoc.gmk	Thu Dec 01 08:56:28 2016 +0000
@@ -33,7 +33,7 @@
 # Allow custom to overwrite.
 JAVADOC_SOURCE_DIRS = \
       $(SUPPORT_OUTPUTDIR)/gensrc/* \
-      $(if $(IMPORT_MODULES_SRC), $(IMPORT_MODULES_SRC)/*) \
+      $(addsuffix /*, $(IMPORT_MODULES_SRC)) \
       $(JDK_TOPDIR)/src/*/$(OPENJDK_TARGET_OS)/classes \
       $(JDK_TOPDIR)/src/*/$(OPENJDK_TARGET_OS_TYPE)/classes \
       $(JDK_TOPDIR)/src/*/share/classes \