Despite setting the CMAKE_CXX_COMPILER and CMAKE_C_COMPILER in CMake, doing make on the Makefiles generated by CMake invokes the clang linker. 
I want it to use the system g++and gcc compiler. I am on OSX Sierra. 
Am I missing a setting somewhere? Here is my CMake setting screenshot.
With clang, I can't get a C++ library compiled as it cannot find libpng which is sitting right in my \usr\local\lib. I thought I give it a go with system g++ and gcc compilers.   

