Use sdk as the bootstrap classpath while compiling against sdk.

Change-Id: Iad16b8c03d88d138abee5e24433b6a654fa21410
http://b/issue?id=2623361
diff --git a/core/base_rules.mk b/core/base_rules.mk
index 0ad797a..5ce7640 100644
--- a/core/base_rules.mk
+++ b/core/base_rules.mk
@@ -319,8 +319,14 @@
 ifeq ($(my_prefix),TARGET_)
 ifeq ($(LOCAL_SDK_VERSION),)
 $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_BOOTCLASSPATH := -bootclasspath $(call java-lib-files,core)
-endif
-endif
+else
+ifeq ($(LOCAL_SDK_VERSION),current)
+$(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_BOOTCLASSPATH := -bootclasspath $(call java-lib-files,android_stubs_current)
+else
+$(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_BOOTCLASSPATH := -bootclasspath $(call java-lib-files,sdk_v$(LOCAL_SDK_VERSION))
+endif # current
+endif # LOCAL_SDK_VERSION
+endif # TARGET_
 $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_RESOURCE_DIR := $(LOCAL_RESOURCE_DIR)
 $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_EXTRA_JAR_ARGS := $(extra_jar_args)
 $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_ASSET_DIR := $(LOCAL_ASSET_DIR)