build: rework gtest checks

Rework gtest checks to be modeled after openbmc/gpioplus.

Change-Id: I068238ba11a4670bba0cde31c77d0b21206efb49
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/test/Makefile.am b/test/Makefile.am
index 431b617..3f78dda 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -1,14 +1,15 @@
-AM_CPPFLAGS = -I$(top_srcdir)/ \
+AM_CPPFLAGS = \
+	-I$(top_srcdir)/ \
 	-I$(top_srcdir)/tools/ \
 	$(GTEST_CFLAGS) \
 	$(GMOCK_CFLAGS)
 AM_CXXFLAGS = \
-	$(GTEST_MAIN_CFLAGS) \
 	$(SDBUSPLUS_CFLAGS) \
 	$(PHOSPHOR_LOGGING_CFLAGS)
 AM_LDFLAGS = \
+	$(GTEST_LIBS) \
 	$(GMOCK_LIBS) \
-	$(GTEST_MAIN_LIBS) \
+	-lgmock_main \
 	$(OESDK_TESTCASE_FLAGS) \
 	$(SDBUSPLUS_LIBS) \
 	$(PHOSPHOR_LOGGING_LIBS)