Add library test makefile solutions.

Change-Id: Ibc8df9b0e2342683158936bf011425780df8f02a
diff --git a/core/host_native_test.mk b/core/host_native_test.mk
index a631364..b54bd3a 100644
--- a/core/host_native_test.mk
+++ b/core/host_native_test.mk
@@ -3,13 +3,6 @@
 ## Common flags for host native tests are added.
 ################################################
 
-LOCAL_CFLAGS += -DGTEST_OS_LINUX -DGTEST_HAS_STD_STRING -O0 -g
-LOCAL_C_INCLUDES +=  \
-    external/gtest/include
-
-LOCAL_STATIC_LIBRARIES += libgtest_host libgtest_main_host
-LOCAL_SHARED_LIBRARIES +=
-
-LOCAL_LDFLAGS += -lpthread
+include $(BUILD_SYSTEM)/host_test_internal.mk
 
 include $(BUILD_HOST_EXECUTABLE)