Undefined reference to process(std::__cxx11::basic_string ... ) when compiling affdex linux sample applications

I encountered the following error when I tried to compile affdex sdk sample applications

Linking CXX executable video-demo
CMakeFiles/http://ift.tt/1W6dLfP: In function 'main':
video-demo.cpp:(.text+0x11cb): undefined reference to 
affdex::VideoDetector::process(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)
collect2: error: ld returned 1 exit status

I'm using GCC 5.2.1