JulesThuillier

gcc\g++ - correct. don't need to do anything with IS_LIB64 - since it's only selection for if. maybe need to set --prefix for autogen.sh to something like /usr/local instead of local dir.
 
libcam_engine_cifisp.so/libcam_ia.so is normal ELF 64-bit LSB objects, ARM aarch64 (you can check it with file utility)
 
PS: camera already working 12+ hours with gstreamer/opencv. with warnings\errors in dmesg, but without memory leaks
PPS: just in case - 64bit SO in attachment
libcam_engine_cifisp.so
libcam_ia.so

thanks to returning me to this thread
 
original FriendlyElec distro use gstreamer-camera  instead of   gstreamer-plugins/extra - which I expect - thats a trick  
( from github.com/rockchip-linux/ repos)
 
never get more than 20 minutes with camera\OpenCV with FriendlyElec distro, but with Armbian already 1.5+ hour and looks like no so big memory leaks.
continue testing
upd: 1.7h with opencv/canny - it's a not bad result, but not exactly what I need
RKISP continue to drops warning/errors due to FIFO overflow.

What is required to get the OV5640 working on a orangePI PC?  Is it possible to use the latest (sunxi) 4.8.x ?