Cmake link libmapnik c++ - c++

Question

I am unable to connect Mapnik via cmake to my application.
I tried to do like this:
cmake_minimum_required(VERSION 3.1)
project(MapnikTest)
set(MAPNIK_LIB "/usr/local/lib/libmapnik.so.3.1.0") dont work
#set(MAPNIK_LIB "/usr/local/lib/libmapnik.so") dont work
set(MAPNIK_INCLUDE_DIR "/usr/local/include/mapnik") work
#find_package(mapnik REQUIRED) dont work
#find_package(Mapnik REQUIRED) dont work
include_directories(${MAPNIK_INCLUDE_DIR})
add_executable(${PROJECT_NAME} main.cpp)
target_link_libraries(${PROJECT_NAME} PRIVATE ${MAPNIK_LIB})
The thing is, I don't have mapnikConfig.cmake in /usr/local/bin/cmake
Can't connect the library directly. Include he sees.
I edited already LD_LIBRARY_PATH it didn't help either.
/usr/bin/ld: CMakeFiles/MapnikTest.dir/main.cpp.o: in function `main':
main.cpp:(.text+0x3b): undefined reference to `mapnik::Map::Map(int, int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
/usr/bin/ld: main.cpp:(.text+0xb8): undefined reference to `mapnik::load_map(mapnik::Map&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, bool, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)'
/usr/bin/ld: main.cpp:(.text+0x1b9): undefined reference to `void mapnik::save_to_file<mapnik::image<mapnik::rgba8_t> >(mapnik::image<mapnik::rgba8_t> const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
/usr/bin/ld: CMakeFiles/MapnikTest.dir/main.cpp.o: in function `icu_66::UnicodeString::hashCode() const':
main.cpp:(.text._ZNK6icu_6613UnicodeString8hashCodeEv[_ZNK6icu_6613UnicodeString8hashCodeEv]+0x18): undefined reference to `icu_66::UnicodeString::doHashCode() const'
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/MapnikTest.dir/build.make:104: MapnikTest] Error 1
make[1]: *** [CMakeFiles/Makefile2:95: CMakeFiles/MapnikTest.dir/all] Error 2
make: *** [Makefile:103: all] Error 2
(dont work mean this)

Answer 1

Find where you have mapnikConfig.cmake or mapnik-config.cmake and set mapnik_DIR to it. Like this:
cmake -Dmapnik_DIR="/path/to/config" ..
and it should be
find_package(mapnik REQUIRED)

Answer 2

Edit
When I inspect github more carefully it turn out that cmake config was introduced recently, after last release. So my answer will become valid for next release of this library.
You can inspect this change to see how import that library.
Original (valid after next release 3.2):
Based on demo form Mapnik repo it should go like this:
cmake_minimum_required(VERSION 3.1)
project(MapnikTest)
find_package(mapnik REQUIRED)
add_executable(${PROJECT_NAME} main.cpp)
target_link_libraries(${PROJECT_NAME} PRIVATE mapnik::agg mapnik::mapnik)
Didn't test it, but should work. I can see library provides proper config.