Linking problems with yaml-cpp

I am trying to incorporate yaml-cpp into my project. I have a "Demes" class where I need to parse a YAML file.

This is the relevant method in Demes.cpp:

#include "Demes.hpp"

void Demes::parse(const std::string& fileName)
{
    YAML::Node test = YAML::LoadFile(fileName);
}

where Demes.hpp includes the yaml-cpp headers and declares the 'parse' method. Building with make -VERBOSE=1 (as suggested by @Tsyvarev) gives:

[100%] Linking CXX executable momentspp cd /home/gvbarroso/Devel/momentspp/build/src && /usr/bin/cmake -E cmake_link_script CMakeFiles/momentspp.dir/link.txt --verbose=1 /usr/bin/c++ -std=c++20 -Weffc++ -Wshadow -Wall -Wextra -ffast-math -O3 -march=native CMakeFiles/momentspp.dir/Log.cpp.o CMakeFiles/momentspp.dir/PolymorphismData.cpp.o CMakeFiles/momentspp.dir/SumStatsLibrary.cpp.o CMakeFiles/momentspp.dir/Drift.cpp.o CMakeFiles/momentspp.dir/Migration.cpp.o CMakeFiles/momentspp.dir/Mutation.cpp.o CMakeFiles/momentspp.dir/Recombination.cpp.o CMakeFiles/momentspp.dir/Epoch.cpp.o CMakeFiles/momentspp.dir/Model.cpp.o CMakeFiles/momentspp.dir/OptimizationWrapper.cpp.o CMakeFiles/momentspp.dir/Demes.cpp.o CMakeFiles/momentspp.dir/main.cpp.o -o momentspp -Wl,-rpath,/home/gvbarroso/.local/lib: /home/gvbarroso/.local/lib/libbpp-phyl3.so.1.0.0 /usr/lib/x86_64-linux-gnu/libboost_iostreams.so.1.74.0 /home/gvbarroso/.local/lib/libbpp-seq3.so.1.0.0 /home/gvbarroso/.local/lib/libbpp-core3.so.1.0.0 /usr/bin/ld: CMakeFiles/momentspp.dir/Demes.cpp.o: in function Demes::parse(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)': Demes.cpp:(.text+0x4c): undefined reference to YAML::LoadFile(std::__cxx11::basic_string<char, std::char_traits, std::allocator > const&)' /usr/bin/ld: Demes.cpp:(.text+0x12c): undefined reference to `YAML::operator<<(std::ostream&, YAML::Node const&)' collect2: error: ld returned 1 exit status make[2]: *** [src/CMakeFiles/momentspp.dir/build.make:277: src/momentspp] Error 1 make[2]: Leaving directory '/home/gvbarroso/Devel/momentspp/build' make[1]: *** [CMakeFiles/Makefile2:125: src/CMakeFiles/momentspp.dir/all] Error 2 make[1]: Leaving directory '/home/gvbarroso/Devel/momentspp/build' make: *** [Makefile:156: all] Error 2

I am using CMake to build my project, but I am still fairly unfamiliar with it.

EDIT: I forgot to mention that I have two CMakeLists.txt files, one inside src and the other inside the external build.

The start of my CMakeLists.txt file in the external build is:

cmake_minimum_required (VERSION 3.5.0)
project (momentspp CXX)

SET(CMAKE_CXX_FLAGS "-std=c++20 -Weffc++ -Wshadow -Wall -Wextra -ffast-math -O3 -march=native")

And the part of it where I look for yaml-cpp is:

FIND_PACKAGE(yaml-cpp REQUIRED)
IF(yaml-cpp_FOUND)
    INCLUDE_DIRECTORIES(${yaml-cpp_INCLUDE_DIRS})
    SET(LIBS {yaml-cpp_LIBRARIES})
    MESSAGE("-- yaml-cpp libraries found here:")
    MESSAGE(" includes: ${yaml-cpp_INCLUDE_DIRS}")
ENDIF()

My full CMakeLists.txt file inside src is:

 SET(momentspp_CPP
  Log.cpp
  PolymorphismData.cpp
  SumStatsLibrary.cpp
  Drift.cpp
  Migration.cpp
  Mutation.cpp
  Recombination.cpp
  Epoch.cpp
  Model.cpp
  OptimizationWrapper.cpp
  Demes.cpp
  main.cpp
)

ADD_EXECUTABLE (momentspp ${momentspp_CPP})

SET(momentspp-targets momentspp)

FOREACH (target ${momentspp-targets})
    TARGET_LINK_LIBRARIES(${target} ${BPP_LIBS_SHARED} ${BOOST_LIBS_SHARED} ${EIGEN3_LIBS_SHARED} ${yaml-cpp_LIBS_SHARED})
   TARGET_LINK_LIBRARIES (${target} ${LIBS})
ENDFOREACH (target)

INSTALL(TARGETS ${momentspp-targets} DESTINATION ${CMAKE_INSTALL_BINDIR})

and this was working prior to the inclusion of yaml-cpp.

This feels like a rather complicated CMake set-up, but I am copying and editing it from a previous project where someone else helped me with it.

How can I fix the linking issue? I tried looking similar questions around here, but couldn't get their solutions to work for me (apparently those people where not using CMake to build their projects).

Thank you, Gustavo