i.e. the libraries that should be in folder: c:\opencv\build\x64\mingw\lib. Only the VC12 and VC14 libraries are available in OpenCV3.1.0
Is there an alternative to compiling them (i.e. https://zahidhasan.wordpress.com/2013/02/16/how-to-install-opencv-on-windows-7-64bit-using-mingw-64-and-codeblocks/)