Makefile change for build against historical sdk versions.

If LOCAL_SDK_VERSION is current, link against the stub, otherwise
link against prebuilt historical sdk
diff --git a/core/java.mk b/core/java.mk
index d57ffca..fc28abf 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -20,7 +20,11 @@
       $(error $(LOCAL_PATH): Invalid LOCAL_SDK_VERSION '$(LOCAL_SDK_VERSION)' \
              Choices are: $(TARGET_AVAILABLE_SDK_VERSIONS))
     else
-      LOCAL_JAVA_LIBRARIES := android_stubs_$(LOCAL_SDK_VERSION) $(LOCAL_JAVA_LIBRARIES) 
+      ifeq ($(LOCAL_SDK_VERSION),current)
+        LOCAL_JAVA_LIBRARIES := android_stubs_$(LOCAL_SDK_VERSION) $(LOCAL_JAVA_LIBRARIES)
+      else
+        LOCAL_JAVA_LIBRARIES := sdk_v$(LOCAL_SDK_VERSION) $(LOCAL_JAVA_LIBRARIES)
+      endif
     endif
   endif
 else