Fix compilation by enabling c++11
Fix compilation by enabling c++11

For some compilers, it is still not the default…
siddharudh/mlt,mltframework/mlt,siddharudh/mlt,j-b-m/mlt,j-b-m/mlt,mltframework/mlt,siddharudh/mlt,siddharudh/mlt,mltframework/mlt,j-b-m/mlt,mltframework/mlt,siddharudh/mlt,mltframework/mlt,j-b-m/mlt,j-b-m/mlt,mltframework/mlt,j-b-m/mlt,siddharudh/mlt,mltframework/mlt,siddharudh/mlt,j-b-m/mlt,siddharudh/mlt,j-b-m/mlt,mltframework/mlt,mltframework/mlt,j-b-m/mlt,mltframework/mlt,j-b-m/mlt,siddharudh/mlt