undefined reference to `USER_ERROR__inconsistent_build_configuration__see_dlib_faq_1_' - c++

Question

So when I use the command make I get the following error:
[jalal#goku c++]$ make
[ 25%] Building CXX object CMakeFiles/TestSVM.dir/TestSVM.cpp.o
[ 50%] Linking CXX executable TestSVM
CMakeFiles/TestSVM.dir/TestSVM.cpp.o: In function `__static_initialization_and_destruction_0(int, int)':
TestSVM.cpp:(.text+0x28c3): undefined reference to `USER_ERROR__inconsistent_build_configuration__see_dlib_faq_1_'
TestSVM.cpp:(.text+0x28cf): undefined reference to `USER_ERROR__inconsistent_build_configuration__see_dlib_faq_2'
collect2: error: ld returned 1 exit status
make[2]: *** [TestSVM] Error 1
make[1]: *** [CMakeFiles/TestSVM.dir/all] Error 2
make: *** [all] Error 2
The files look like:
[jalal#goku c++]$ ls
CMakeCache.txt CMakeFiles CMakeLists.txt Makefile TestSVM.cpp TrainSVM.cpp cmake_install.cmake json.hpp trained_svms
I built the dlib in /scratch2/dlib from source using this repo:https://github.com/davisking/dlib
by following these commands:
mkdir build; cd build; cmake .. -DUSE_AVX_INSTRUCTIONS=1; cmake --build .
I am not sure how I should fix this problem.
I followed the following commands in the git repo I cloned:
$ cd c++
$ cmake .
$ make
https://github.com/sausax/pose_estimation
Additionally not sure how to make sense out of this for fixing the bug
https://github.com/davisking/dlib/blob/master/dlib/test_for_odr_violations.cpp

Answer 1

As the commenter said, don't forget to link to dlib! You can do this in CMake with:
target_link_libraries(<YOUR APP> dlib::dlib)
I wasn't able to get plain dlib to link, but I tried ${dlib_LIBRARIES} and finally CMake clued me in with:
CMake Warning at lib/cmake/dlib/dlibConfig.cmake:42 (message):
The variable 'dlib_LIBRARIES' is deprecated! Instead, simply use
target_link_libraries(your_app dlib::dlib). See
http://dlib.net/examples/CMakeLists.txt.html for an example.
I too was distracted by the ENABLE_ASSERTS pointing to the FAQ, but that was due to me having the includes without the linked library.