Exclude only modules with prebuilt in prebuilts/sdk.

So we can do tapas build in the full platform source tree.

Change-Id: I4c64d1007d1e295518ed6338b46d1087714b68aa
(cherry picked from commit 9dd567a7d5)

Android.mk

@@ -14,9 +14,6 @@
 # limitations under the License.
 #
 
-# Don't build for unbundled branches
-ifeq (,$(TARGET_BUILD_APPS))
-
 LOCAL_PATH := $(call my-dir)
 
 LIBCXX_SRC_FILES := \
@@ -101,6 +98,9 @@ endif
 LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk
 include $(BUILD_HOST_STATIC_LIBRARY)
 
+# Don't build for unbundled branches
+ifeq (,$(TARGET_BUILD_APPS))
+
 # host dynamic lib
 include $(CLEAR_VARS)
 LOCAL_MODULE := libc++