Add explicit support library prebuilts targets

We won't be updating prebuilts/sdk. Apps need to move to fullsdk if they
need a current prebuilt version of the support library.

Test: make
Test: make ANDROID_BUILDSPEC=vendor/google/build/app_build_spec.mk
Change-Id: I122ff2cd06daed673c9c2f6413c305cce0230e58
diff --git a/current/Android.mk b/current/Android.mk
index 11b4f96..acddb1f 100644
--- a/current/Android.mk
+++ b/current/Android.mk
@@ -18,7 +18,9 @@
 
 #########################################
 # The prebuilt support libraries.
-# Only needed for unbundled build.
+
+# For apps (unbundled) build, replace the typical
+# make target artifacts with prebuilts.
 ifneq ($(TARGET_BUILD_APPS),)
 include $(CLEAR_VARS)
 LOCAL_PREBUILT_STATIC_JAVA_LIBRARIES := \
@@ -26,3 +28,14 @@
     $(shell find $(LOCAL_PATH)/support -name "*.jar"))
 include $(BUILD_MULTI_PREBUILT)
 endif  # TARGET_BUILD_APPS not empty
+
+# Also set up explicit prebuilts for use in apps.
+include $(CLEAR_VARS)
+SUPPORT_LIBS := \
+  $(patsubst $(LOCAL_PATH)/%,%,\
+    $(shell find $(LOCAL_PATH)/support -name "*.jar"))
+LOCAL_PREBUILT_STATIC_JAVA_LIBRARIES := \
+  $(foreach lib,$(SUPPORT_LIBS),\
+    $(basename $(notdir $(lib)))-prebuilt:$(lib))
+SUPPORT_LIBS :=
+include $(BUILD_MULTI_PREBUILT)