Rename is_unbundled_app_build and UNBUNDLED_APP_BUILD to TARGET_BUILD_APPS.

Change-Id: I79e6f60e009dad3a48709962347441e4ca0c337a
diff --git a/core/package.mk b/core/package.mk
index e7be05f..cdeefb4 100644
--- a/core/package.mk
+++ b/core/package.mk
@@ -311,7 +311,7 @@
 # Define the rule to build the actual package.
 $(LOCAL_BUILT_MODULE): $(AAPT) | $(ZIPALIGN)
 $(LOCAL_BUILT_MODULE): PRIVATE_JNI_SHARED_LIBRARIES := $(jni_shared_libraries)
-ifeq ($(strip $(is_unbundled_app_build)),true)
+ifneq ($(TARGET_BUILD_APPS),)
     # Include all resources for unbundled apps.
     $(LOCAL_BUILT_MODULE): PRODUCT_AAPT_CONFIG :=
 endif