CMake finds boost libraries but Make fails to link them - c++

Question

After coming back to a project after a month I am able to run CMake successfully with the following output
-- Boost version: 1.61.0
-- Found the following Boost libraries:
-- system
-- thread
-- filesystem
-- chrono
-- date_time
-- atomic
-- Configuring done
-- Generating done
-- Build files have been written to: /Users/LittleNewt/gitness/MangaMeCLI/build
but for some reason when running Make on the generated MakeFile I get the following output
[ 50%] Building CXX object CMakeFiles/mangaMeCLI.dir/src/mangaMeCLI.cpp.o
[100%] Linking CXX executable mangaMeCLI
Undefined symbols for architecture x86_64:
"boost::filesystem::path::operator/=(char const*)", referenced from:
_main in mangaMeCLI.cpp.o
"boost::filesystem::path::operator/=(boost::filesystem::path const&)", referenced from:
boost::filesystem::path::operator/=(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >&) in mangaMeCLI.cpp.o
boost::filesystem::path::operator/=(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) in mangaMeCLI.cpp.o
"boost::filesystem::detail::current_path(boost::system::error_code*)", referenced from:
boost::filesystem::current_path() in mangaMeCLI.cpp.o
"boost::filesystem::detail::create_directory(boost::filesystem::path const&, boost::system::error_code*)", referenced from:
boost::filesystem::create_directory(boost::filesystem::path const&) in mangaMeCLI.cpp.o
"boost::filesystem::detail::status(boost::filesystem::path const&, boost::system::error_code*)", referenced from:
boost::filesystem::exists(boost::filesystem::path const&) in mangaMeCLI.cpp.o
boost::filesystem::is_directory(boost::filesystem::path const&) in mangaMeCLI.cpp.o
"boost::system::system_category()", referenced from:
___cxx_global_var_init.75 in mangaMeCLI.cpp.o
"boost::system::generic_category()", referenced from:
___cxx_global_var_init.73 in mangaMeCLI.cpp.o
___cxx_global_var_init.74 in mangaMeCLI.cpp.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [mangaMeCLI] Error 1
make[1]: *** [CMakeFiles/mangaMeCLI.dir/all] Error 2
make: *** [all] Error 2
I did some research and have found others having the same issues due to not linking the correct version of the libraries for there architecture (64bit vs 32bit) but am not sure how to identify if this is the issue for me.
Here is my unchanged CMakeLists.txt file
CMAKE_MINIMUM_REQUIRED(VERSION 3.4.1)
PROJECT(MangaMeCLI)
SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
INCLUDE_DIRECTORIES(includes)
ADD_EXECUTABLE(mangaMeCLI src/mangaMeCLI.cpp)
MESSAGE("${CMAKE_CXX_FLAGS}")
SET(Boost_USE_MULTITHREADED ON)
FIND_PACKAGE(Boost REQUIRED COMPONENTS system thread filesystem)
INCLUDE_DIRECTORIES(${BOOST_INCLUDE_DIRS})
TARGET_LINK_LIBRARIES(mangaMeCLI ${BOOST_LIBRARIES})
SET(OPENSSL_ROOT_DIR /usr/local/Cellar/openssl/*)
FIND_PACKAGE(OpenSSL REQUIRED)
INCLUDE_DIRECTORIES(${OPENSSL_INCLUDE_DIR})
TARGET_LINK_LIBRARIES(mangaMeCLI ${OPENSSL_LIBRARIES})
FIND_PACKAGE(cppnetlib REQUIRED)
INCLUDE_DIRECTORIES(${CPPNETLIB_INCLUDE_DIRS})
TARGET_LINK_LIBRARIES(mangaMeCLI ${CPPNETLIB_LIBRARIES})
After reading a useful comment I found that the BOOST_LIBRARIES variable was empty even though cmake prints that it found the boost libraries I was looking for. I am assuming this is the reason for my error.

Answer 1

CMake variables are case-sensitive. As per the find module's documentation, you want Boost_LIBRARIES, not BOOST_LIBRARIES:
INCLUDE_DIRECTORIES(${Boost_INCLUDE_DIRS})
TARGET_LINK_LIBRARIES(mangaMeCLI ${Boost_LIBRARIES})