Stop building host native test in unbundled build

It turned out that building native code for host environment
is not supported in NDK build.  Hence this CL makes the host
native test available only as a part of platform build to
avoid accidental build breakage in unbundled build.

BUG: 18095678
Change-Id: If608da166d5a478358e6890b8db526b4c2c0ab41

native/jni/HostUnitTests.mk

@@ -12,6 +12,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# Host build is never supported in unbundled (NDK/tapas) build
+ifeq (,$(TARGET_BUILD_APPS))
+
 # HACK: Temporarily disable host tool build on Mac until the build system is ready for C++11.
 LATINIME_HOST_OSNAME := $(shell uname -s)
 ifneq ($(LATINIME_HOST_OSNAME), Darwin) # TODO: Remove this
@@ -47,10 +50,13 @@ LOCAL_SRC_FILES := $(addprefix $(LATIN_IME_TEST_SRC_DIR)/, $(LATIN_IME_CORE_TEST
 LOCAL_STATIC_LIBRARIES += liblatinime_host_static_for_unittests
 include $(BUILD_HOST_NATIVE_TEST)
 
+include $(LOCAL_PATH)/CleanupNativeFileList.mk
+
 endif # Darwin - TODO: Remove this
 
+endif # TARGET_BUILD_APPS
+
 #################### Clean up the tmp vars
 LATINIME_HOST_OSNAME :=
 LATIN_IME_SRC_DIR :=
 LATIN_IME_TEST_SRC_DIR :=
-include $(LOCAL_PATH)/CleanupNativeFileList.mk

native/jni/run-tests.sh

@@ -48,6 +48,13 @@ if [[ $show_usage == yes ]]; then
   if [[ ${BASH_SOURCE[0]} != $0 ]]; then return; else exit 1; fi
 fi
 
+# Host build is never supported in unbundled (NDK/tapas) build
+if [[ $enable_host_test == yes && -n $TARGET_BUILD_APPS ]]; then
+  echo "Host build is never supported in tapas build."  1>&2
+  echo "Use lunch command instead."  1>&2
+  if [[ ${BASH_SOURCE[0]} != $0 ]]; then return; else exit 1; fi
+fi
+
 target_test_name=liblatinime_target_unittests
 host_test_name=liblatinime_host_unittests