Cmake设置将外部c++类添加到项目中

可能有点小问题，请耐心等待。

我想做什么？我有一个名为main.cpp的c++类，我想用它添加RtMidi的外部类。我可以将RtMidi类移到与我的main.cpp相同的文件夹中，并从那里包含它们，但如果我能将它们放在一个单独的文件夹中会感觉干净得多。

RtMidi文件夹有自己的Cmake文件，我的假设是，我可以首先构建该文件夹，创建一个库，然后链接到该库。这是正确的吗？我是c++的新手，不能100%确定这是否是添加外部类的方式。

当试图构建我的项目RtMidi时，我得到了一个警告，即main.cpp文件找不到include。

我正在用Visual Studio代码和clang作为编译器的mac上构建这个，如果这对有帮助的话

main.cpp

#include "RtMidi.h"
int main() 
{
try 
{
RtMidiIn midiin;
} 
catch (RtMidiError &error) 
{
error.printMessage();
}
return 0;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.0.0)
project(Music)
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
include_directories (Project)
add_subdirectory (lib/rtmidi-4.0.0)
file(GLOB_RECURSE SOURCES RELATIVE ${CMAKE_SOURCE_DIR} "src/*.cpp")
add_executable(Music ${SOURCES})
target_link_libraries(Music RtMidi)

生成输出

[main] Building folder: Music 
[main] Configuring folder: Music 
[proc] Executing command: /usr/local/bin/cmake --no-warn-unused-cli -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=TRUE -DCMAKE_BUILD_TYPE:STRING=Debug -DCMAKE_C_COMPILER:FILEPATH=/usr/bin/clang -DCMAKE_CXX_COMPILER:FILEPATH=/usr/bin/clang++ -H/Users/username/Code/Music -B/Users/username/Code/Music/build -G "Unix Makefiles"
[cmake] Not searching for unused variables given on the command line.
[cmake] -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) 
[cmake] CMake Deprecation Warning at lib/rtmidi-4.0.0/CMakeLists.txt:154 (cmake_policy):
[cmake]   The OLD behavior for policy CMP0042 will be removed from a future version
[cmake]   of CMake.
[cmake] 
[cmake]   The cmake-policies(7) manual explains that the OLD behaviors of all
[cmake]   policies are deprecated and that a policy should be set to OLD only under
[cmake]   specific short-term circumstances.  Projects should be ported to the NEW
[cmake]   behavior and not rely on setting a policy to OLD.
[cmake] 
[cmake] 
[cmake] -- Compiling with support for: coremidi
[cmake] -- Configuring done
[cmake] -- Generating done
[cmake] -- Build files have been written to: /Users/username/Code/Music/build
[build] Starting build
[proc] Executing command: /usr/local/bin/cmake --build /Users/username/Code/Music/build --config Debug --target all -- -j 10
[build] Scanning dependencies of target Music
[build] [ 15%] Built target rtmidi
[build] [ 20%] Building CXX object CMakeFiles/Music.dir/src/main.cpp.o
[build] [ 40%] Built target sysextest
[build] [ 40%] Built target qmidiin
[build] [ 50%] Built target apinames
[build] [ 60%] Built target midiout
[build] [ 80%] Built target cmidiin
[build] [ 80%] Built target midiprobe
[build] [ 90%] Built target midiclock
[build] /Users/username/Code/Music/src/main.cpp:5:10: fatal error: 'rtmidi.h' file not found
[build] #include "rtmidi.h"
[build]          ^~~~~~~~~~
[build] 1 error generated.
[build] make[2]: *** [CMakeFiles/Music.dir/src/main.cpp.o] Error 1
[build] make[1]: *** [CMakeFiles/Music.dir/all] Error 2
[build] make: *** [all] Error 2
[build] Build finished with exit code 2

感谢您的帮助，如果这是错误的做法，请为我指明正确的方向来进行