OpenCV 3.x explicitly does not support pure C compilation, build fails with 3.4+

[AdamWill]

Building simarrange with OpenCV 3.4+ fails due to this problem. As discussed there, OpenCV is just not interested in supporting pure C compilation any more, it expects only C++ code to use it.

Just building simarrange as C++ (i.e. with g++ instead of gcc) seems to work fine, FWIW. So could just change the Makefile to do that, I guess.