Only copy once even if the first matched src:dest pair appears more than once.

Change-Id: I9bef6172a1123518e97e04190fb857f9ee2c7582
diff --git a/core/Makefile b/core/Makefile
index 12ae657..7ba33a6 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -15,15 +15,18 @@
 # <dest file> is relative to $(PRODUCT_OUT), so it should look like,
 # e.g., "system/etc/file.xml".
 # The filter part means "only eval the copy-one-file rule if this
-# src:dest pair is the first one to match %:dest"
+# src:dest pair is the first one to match the same dest"
+unique_product_copy_files_destinations := $(sort \
+    $(foreach cf,$(PRODUCT_COPY_FILES), $(call word-colon,2,$(cf))))
 $(foreach cf,$(PRODUCT_COPY_FILES), \
-  $(eval _src := $(call word-colon,1,$(cf))) \
-  $(eval _dest := $(call word-colon,2,$(cf))) \
-  $(eval _fulldest := $(call append-path,$(PRODUCT_OUT),$(_dest))) \
-  $(if $(filter $(_src):$(_dest),$(firstword $(filter %:$(_dest),$(PRODUCT_COPY_FILES)))), \
-    $(eval $(call copy-one-file,$(_src),$(_fulldest))),) \
-  $(eval ALL_DEFAULT_INSTALLED_MODULES += $(_fulldest)) \
- )
+    $(eval _src := $(call word-colon,1,$(cf))) \
+    $(eval _dest := $(call word-colon,2,$(cf))) \
+    $(if $(filter $(unique_product_copy_files_destinations),$(_dest)), \
+        $(eval _fulldest := $(call append-path,$(PRODUCT_OUT),$(_dest))) \
+        $(eval $(call copy-one-file,$(_src),$(_fulldest))) \
+        $(eval ALL_DEFAULT_INSTALLED_MODULES += $(_fulldest)) \
+        $(eval unique_product_copy_files_destinations := $(filter-out $(_dest), \
+            $(unique_product_copy_files_destinations)))))
 
 # -----------------------------------------------------------------
 # docs/index.html