链接器错误-在ubuntu中找不到CMake和Cuda 10.1的lcudart

我正试图用CMake构建一个非常简单的cuda示例。该示例调用cudaGetDeviceCount函数。我从另一篇帖子中了解到，我需要将其与cudart库链接。我得到这个错误：

Found CUDA installation: /usr/local/cuda, version unknown
"/usr/bin/ld" -z relro --hash-style=gnu --eh-frame-hdr -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 -o testcuda /usr/bin/../lib/gcc/x86_64-linux-gnu/7.4.0/../../../x86_64-linux-gnu/crt1.o /usr/bin/../lib/gcc/x86_64-linux-gnu/7.4.0/../../../x86_64-linux-gnu/crti.o /usr/bin/../lib/gcc/x86_64-linux-gnu/7.4.0/crtbegin.o -L/usr/bin/../lib/gcc/x86_64-linux-gnu/7.4.0 -L/usr/bin/../lib/gcc/x86_64-linux-gnu/7.4.0/../../../x86_64-linux-gnu -L/lib/x86_64-linux-gnu -L/lib/../lib64 -L/usr/lib/x86_64-linux-gnu -L/usr/bin/../lib/gcc/x86_64-linux-gnu/7.4.0/../../.. -L/usr/lib/llvm-6.0/bin/../lib -L/lib -L/usr/lib CMakeFiles/testcuda.dir/main.cpp.o -lcuda -lcudart -L/usr/local/cuda/lib64/stubs -L. -lstdc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /usr/bin/../lib/gcc/x86_64-linux-gnu/7.4.0/crtend.o /usr/bin/../lib/gcc/x86_64-linux-gnu/7.4.0/../../../x86_64-linux-gnu/crtn.o
/usr/bin/ld: cannot find -lcudart

这是我的CMakeLists.txt.

cmake_minimum_required(VERSION 3.15)
project (testcuda CXX CUDA)
if (NOT DEFINED CMAKE_CXX_STANDARD)
set (CMAKE_CXX_STANDARD_17)
set (CMAKE_CXX_STANDARD_REQUIRED True)
endif()
if (NOT DEFINED CMAKE_CUDA_STANDARD)
set (CMAKE_CUDA_STANDARD_17)
set (CMAKE_CUDA_STANDARD_REQUIRED True)
endif()
set (CMAKE_EXE_LINKER_FLAGS -v)
add_executable (testcuda main.cpp)
target_include_directories(testcuda PRIVATE ${CMAKE_CUDA_TOOLKIT_INCLUDE_DIRECTORIES})
target_link_libraries(testcuda cuda cudart)
MESSAGE (STATUS ${CMAKE_CUDA_TOOLKIT_INCLUDE_DIRECTORIES})
MESSAGE (STATUS ${CUDA_LIBRARIES})
MESSAGE (STATUS ${CUDA_VERSION})

我的libcudart的位置在这里：

/usr/local/cuda-10.1/targets/x86_64-linux/lib/libcudart.so

变量CMAKE_CUDA_TOOLKIT_INCLUDE_DIRECTORIES的输出为/usr/local/cuda/targets/x86_64-linux/include，但CUDA_LIBRARIES和CUDA_VERSION都为空。

我的CMake是3.15。

我错过什么了吗？