--- a/make-rules/prep.mk	Thu Apr 16 01:36:32 2015 -0700
+++ b/make-rules/prep.mk	Mon Apr 20 12:35:51 2015 -0700
@@ -18,7 +18,9 @@
 #
 # CDDL HEADER END
 #
-# Copyright (c) 2010, 2012, Oracle and/or its affiliates. All rights reserved.
+
+#
+# Copyright (c) 2010, 2015, Oracle and/or its affiliates. All rights reserved.
 #
 
 # One must do all unpack and patch in sequence.
@@ -33,7 +35,7 @@
 # In order to override PATCH_DIR and PATCH_PATTERN in component makefiles, they
 # need to be conditionally set here.  This means that the override needs to
 # happen prior to including prep.mk.  Otherwise other variables set here which
-# are based on those will be expanded too early for the override to take 
+# are based on those will be expanded too early for the override to take
 # effect.
 # You also can't override PATCHES after including prep.mk; if you want to
 # append filenames to PATCHES, you'll have to set $(EXTRA_PATCHES) prior to
@@ -71,7 +73,7 @@
 	$$(TOUCH) [email protected]
 endef
 
-# Template for patching rules, note that patching is actually done by the 
+# Template for patching rules, note that patching is actually done by the
 # %.ed pattern rule above.
 # To maintain backwards compatibility, the flag PATCH_EACH_ARCHIVE must
 # be non-empty in order to activate individual archive patching.
@@ -117,7 +119,7 @@
 # Calculate the number of defined archives.
 # Always generate at least the basic prep rules.
 # Work out if there are any other archives to be downloaded and patched.
-NUM_EXTRA_ARCHIVES= 1 2 3 4 5 6 7 8 9
+NUM_EXTRA_ARCHIVES ?= 1 2 3 4 5 6 7 8 9
 $(eval $(call archive-rule,))
 ifneq ($(strip $(PATCH_EACH_ARCHIVE)),)
 $(foreach suffix,$(NUM_EXTRA_ARCHIVES), \