Fix native test static lib.

Change-Id: I2ef5a4c913732a9a3211556493926f4883b4160e
diff --git a/core/native_test.mk b/core/native_test.mk
index 7fe1637..0d88aa5 100644
--- a/core/native_test.mk
+++ b/core/native_test.mk
@@ -8,7 +8,7 @@
                     bionic/libstdc++/include \
                     external/gtest/include \
                     external/stlport/stlport
-LOCAL_STATIC_LIBRARIES +=
+LOCAL_STATIC_LIBRARIES += libgtest libgtest_main
 LOCAL_SHARED_LIBRARIES += libstlport
 
 ifndef LOCAL_MODULE_PATH