Build gtest from source rather than using SDK-provided version

ports/nacl-spawn/Makefile

 # Copyright (c) 2014 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # TODO(hamaji): include $NACL_SDK_ROOT/tools/common.mk.
 
 NACL_SPAWN_OBJS = nacl_spawn.o nacl_setup_env.o path_util.o elf_reader.o \
                   library_dependencies.o nacl_apipe.o nacl_pp_helpers.o
 
 TEST_EXES = test/unittests
 LIBRARIES = libcli_main.a libnacl_spawn.a
 
 CFLAGS += -std=gnu99
 CPPFLAGS += -Wall -Werror -Iinclude
+CPPFLAGS += -I$(GTEST_DIR)/include
 LDFLAGS += -lnacl_io
 
 ifeq ($(NACL_SHARED),1)
 LIBRARIES += libnacl_spawn.so
 endif
 
 ifeq ($(TOOLCHAIN),glibc)
 TEST_EXES += test/elf_reader test/library_dependencies
 TEST_BINARIES = test/test_exe test/libtest1.so test/libtest2.so test/libtest3.so
 endif
@@ skipping 16 matching lines @@
 libnacl_spawn.so: $(NACL_SPAWN_OBJS)
         $(CXX) $(LDFLAGS) -shared $^ -o $@
 
 libnacl_spawn.a: $(NACL_SPAWN_OBJS)
         rm -f $@
         $(AR) rcs $@ $^
 
 %.o: %.cc
         $(CXX) $(CPPFLAGS) $(CXXFLAGS) -c $< -o $@
 
+%.o: $(GTEST_DIR)/src/%.cc
+        $(CXX) $(CPPFLAGS) $(CXXFLAGS) -c $< -o $@ -I$(GTEST_DIR)
+
 # Targets for tests
 
 LIBS=-Xlinker -uPSUserMainGet -lcli_main -lnacl_spawn
-LIBS+=-lgtest -lppapi_simple_cpp -lnacl_io -lppapi_cpp -lppapi
+LIBS+=-lppapi_simple_cpp -lnacl_io -lppapi_cpp -lppapi
 
-test/unittests: nacl_spawn_test.o $(LIBRARIES)
-        $(CXX) -L. $(LDFLAGS) $< -o $@ $(LIBS)
+test/unittests: nacl_spawn_test.o $(LIBRARIES) gtest-all.o
+        $(CXX) -L. $(LDFLAGS) $< gtest-all.o -o $@ $(LIBS)
 
 
 ifeq ($(TOOLCHAIN),glibc)
 test:
         ./test/run_test.sh
 
 test/elf_reader: elf_reader.cc
         $(CXX) $(CPPFLAGS) $(CXXFLAGS) $(LDFLAGS) -DDEFINE_ELF_READER_MAIN $< -o $@
 test/library_dependencies: elf_reader.o path_util.o library_dependencies.cc
         $(CXX) $(CPPFLAGS) $(CXXFLAGS) $(LDFLAGS) -DDEFINE_LIBRARY_DEPENDENCIES_MAIN $^ -o $@
 
 # We use -nostdlib not to have libc.so in their dependencies.
 test/test_exe: test/test_exe.c test/libtest1.so test/libtest2.so
         $(CC) $(CPPFLAGS) $(CFLAGS) $< -nostdlib -Wl,-rpath-link=test -Ltest -ltest1 -ltest2 -o $@
 test/libtest1.so: test/libtest1.c test/libtest3.so
         $(CC) $(CPPFLAGS) $(CFLAGS) $< -fPIC -nostdlib -shared -Ltest -ltest3 -o $@
 test/libtest2.so: test/libtest2.c test/libtest3.so
         $(CC) $(CPPFLAGS) $(CFLAGS) $< -fPIC -nostdlib -shared -Ltest -ltest3 -o $@
 test/libtest3.so: test/libtest3.c
         $(CC) $(CPPFLAGS) $(CFLAGS) $< -fPIC -nostdlib -shared -o $@
 endif
 
 clean:
         rm -f *.a *.o *.so $(TEST_EXES) $(TEST_BINARIES)
 
 .PHONY: clean all test