Fix detection of C++ STL for tests.

Target tests weren't approrpiately using the libc++ gtest for
libc++_static, and the hosts tests were still using the old check.

Change-Id: I13813d5f09673b144b2dfead93eb81cb4bae0e34
diff --git a/core/host_test_internal.mk b/core/host_test_internal.mk
index 426c400..5f0a1f3 100644
--- a/core/host_test_internal.mk
+++ b/core/host_test_internal.mk
@@ -5,7 +5,14 @@
 LOCAL_CFLAGS += -DGTEST_OS_LINUX -DGTEST_HAS_STD_STRING -O0 -g
 LOCAL_C_INCLUDES +=  external/gtest/include
 
-ifneq ($(filter libc++,$(LOCAL_SHARED_LIBRARIES)),)
+my_test_libcxx := false
+ifeq (,$(TARGET_BUILD_APPS))
+ifneq ($(filter $(strip $(LOCAL_CXX_STL)),libc++ libc++_static),)
+my_test_libcxx := true
+endif
+endif
+
+ifeq ($(my_test_libcxx),true)
 LOCAL_STATIC_LIBRARIES += libgtest_libc++_host libgtest_main_libc++_host
 else
 LOCAL_STATIC_LIBRARIES += libgtest_host libgtest_main_host
diff --git a/core/target_test_internal.mk b/core/target_test_internal.mk
index 65def9c..50f4036 100644
--- a/core/target_test_internal.mk
+++ b/core/target_test_internal.mk
@@ -9,7 +9,7 @@
 my_test_libcxx := false
 ifndef LOCAL_SDK_VERSION
 ifeq (,$(TARGET_BUILD_APPS))
-ifeq ($(strip $(LOCAL_CXX_STL)),libc++)
+ifneq ($(filter $(strip $(LOCAL_CXX_STL)),libc++ libc++_static),)
 my_test_libcxx := true
 endif
 endif