Fix unbundled branches

Change-Id: Ic8a58a6cf55221ec361bbb80c7c9636fe1349943
diff --git a/libbacktrace/Android.mk b/libbacktrace/Android.mk
index 13898ec..5a0bc7f 100755
--- a/libbacktrace/Android.mk
+++ b/libbacktrace/Android.mk
@@ -72,6 +72,8 @@
 build_type := host
 include $(LOCAL_PATH)/Android.build.mk
 
+# Don't build for unbundled branches
+ifeq (,$(TARGET_BUILD_APPS))
 #-------------------------------------------------------------------------
 # The libbacktrace library (libc++)
 #-------------------------------------------------------------------------
@@ -112,6 +114,7 @@
 include $(LOCAL_PATH)/Android.build.mk
 build_type := host
 include $(LOCAL_PATH)/Android.build.mk
+endif
 
 #-------------------------------------------------------------------------
 # The libbacktrace_test library needed by backtrace_test.