是什么导致macOS Mojave上的GoogleTest链接错误

我不确定是需要额外的参数来cmake有问题，还是我自己的Makefile有问题。我正在尝试构建和安装谷歌测试，以便在我的一个项目中使用。我在macOS mojave上运行，通过Homebrew安装了cmake。为了安装谷歌测试，我做了以下操作：

git clone https://github.com/google/googletest
cd googletest
mkdir build
cd build
cmake ..
make
make install

我编译了我的源代码和测试文件。以下是Makefile生成的用于编译名为Point2d.cpp:的文件的示例命令

clang++ -arch x86_64 -c -std=c++11 -stdlib=libc++ -O2 -I /usr/local/include -c -o ../build/core/Point2d.o core/Point2d.cpp

然后我尝试链接我的所有对象文件。以下是makefile生成的命令(其中main.o是包含运行测试的主要函数的对象文件(：

clang++ -arch x86_64 ../build/core/Point2d.o ../build/PointTest.o ../build/main.o -o ../bin/test -L /usr/local/lib

导致链接错误：

Undefined symbols for architecture x86_64:
"testing::InitGoogleTest(int*, char**)", referenced from:
_main in main.o
"testing::Test::SetUp()", referenced from:
vtable for Point2dTests_Constructors_Test in PointTest.o
"testing::Test::TearDown()", referenced from:
vtable for Point2dTests_Constructors_Test in PointTest.o
"testing::Test::Test()", referenced from:
testing::internal::TestFactoryImpl<Point2dTests_Constructors_Test>::CreateTest() in PointTest.o
"testing::Test::~Test()", referenced from:
Point2dTests_Constructors_Test::~Point2dTests_Constructors_Test() in PointTest.o
Point2dTests_Constructors_Test::~Point2dTests_Constructors_Test() in PointTest.o
"testing::Message::Message()", referenced from:
Point2dTests_Constructors_Test::TestBody() in PointTest.o
"testing::UnitTest::GetInstance()", referenced from:
_main in main.o
"testing::UnitTest::Run()", referenced from:
_main in main.o
"testing::internal::AssertHelper::AssertHelper(testing::TestPartResult::Type, char const*, int, char const*)", referenced from:
Point2dTests_Constructors_Test::TestBody() in PointTest.o
"testing::internal::AssertHelper::~AssertHelper()", referenced from:
Point2dTests_Constructors_Test::TestBody() in PointTest.o
"testing::internal::GetTestTypeId()", referenced from:
__GLOBAL__sub_I_PointTest.cpp in PointTest.o
"testing::internal::MakeAndRegisterTestInfo(char const*, char const*, char const*, char const*, testing::internal::CodeLocation, void const*, void (*)(), void (*)(), testing::internal::TestFactoryBase*)", referenced from:
__GLOBAL__sub_I_PointTest.cpp in PointTest.o
"testing::internal::GetBoolAssertionFailureMessage(testing::AssertionResult const&, char const*, char const*, char const*)", referenced from:
Point2dTests_Constructors_Test::TestBody() in PointTest.o
"testing::internal::IsTrue(bool)", referenced from:
testing::internal::SuiteApiResolver<testing::Test>::GetSetUpCaseOrSuite(char const*, int) in PointTest.o
testing::internal::SuiteApiResolver<testing::Test>::GetTearDownCaseOrSuite(char const*, int) in PointTest.o
"testing::internal::GTestLog::GTestLog(testing::internal::GTestLogSeverity, char const*, int)", referenced from:
testing::internal::SuiteApiResolver<testing::Test>::GetSetUpCaseOrSuite(char const*, int) in PointTest.o
testing::internal::SuiteApiResolver<testing::Test>::GetTearDownCaseOrSuite(char const*, int) in PointTest.o
"testing::internal::GTestLog::~GTestLog()", referenced from:
testing::internal::SuiteApiResolver<testing::Test>::GetSetUpCaseOrSuite(char const*, int) in PointTest.o
testing::internal::SuiteApiResolver<testing::Test>::GetTearDownCaseOrSuite(char const*, int) in PointTest.o
"testing::internal::AssertHelper::operator=(testing::Message const&) const", referenced from:
Point2dTests_Constructors_Test::TestBody() in PointTest.o
"typeinfo for testing::Test", referenced from:
typeinfo for Point2dTests_Constructors_Test in PointTest.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[1]: *** [../bin/test] Error 1
make: *** [test] Error 2