diff --git a/core/config.mk b/core/config.mk
index 680a169..10c66f5 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -113,6 +113,16 @@
 SHOW_COMMANDS:= $(filter showcommands,$(MAKECMDGOALS))
 hide := $(if $(SHOW_COMMANDS),,@)
 
+################################################################
+# Tools needed in product configuration makefiles.
+################################################################
+NORMALIZE_PATH := build/tools/normalize_path.py
+
+# $(1): the paths to be normalized
+define normalize-paths
+$(if $(1),$(shell $(NORMALIZE_PATH) $(1)))
+endef
+
 # ###############################################################
 # Set common values
 # ###############################################################
@@ -550,8 +560,6 @@
 MD5SUM:=md5sum
 endif
 
-NORMALIZE_PATH := build/tools/normalize_path.py
-
 APICHECK_CLASSPATH := $(HOST_JDK_TOOLS_JAR)
 APICHECK_CLASSPATH := $(APICHECK_CLASSPATH):$(HOST_OUT_JAVA_LIBRARIES)/doclava$(COMMON_JAVA_PACKAGE_SUFFIX)
 APICHECK_CLASSPATH := $(APICHECK_CLASSPATH):$(HOST_OUT_JAVA_LIBRARIES)/jsilver$(COMMON_JAVA_PACKAGE_SUFFIX)
diff --git a/core/product.mk b/core/product.mk
index f242e82..a9af325 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -133,11 +133,14 @@
 #  3. Records that we've visited this node, in ALL_PRODUCTS
 #
 define inherit-product
+  $(if $(findstring ../,$(1)),\
+    $(eval np := $(call normalize-paths,$(1))),\
+    $(eval np := $(strip $(1))))\
   $(foreach v,$(_product_var_list), \
-      $(eval $(v) := $($(v)) $(INHERIT_TAG)$(strip $(1)))) \
+      $(eval $(v) := $($(v)) $(INHERIT_TAG)$(np))) \
   $(eval inherit_var := \
       PRODUCTS.$(strip $(word 1,$(_include_stack))).INHERITS_FROM) \
-  $(eval $(inherit_var) := $(sort $($(inherit_var)) $(strip $(1)))) \
+  $(eval $(inherit_var) := $(sort $($(inherit_var)) $(np))) \
   $(eval inherit_var:=) \
   $(eval ALL_PRODUCTS := $(sort $(ALL_PRODUCTS) $(word 1,$(_include_stack))))
 endef
diff --git a/tools/normalize_path.py b/tools/normalize_path.py
index 1b3d42e..6c4d548 100755
--- a/tools/normalize_path.py
+++ b/tools/normalize_path.py
@@ -14,11 +14,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 """
-Normalize and output paths read from stdin.
+Normalize and output paths from arguments, or stdin if no arguments provided.
 """
 
 import os.path
 import sys
 
+if len(sys.argv) > 1:
+  for p in sys.argv[1:]:
+    print os.path.normpath(p)
+  sys.exit(0)
+
 for line in sys.stdin:
   print os.path.normpath(line.strip())