ayaromenok

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.

Only FriendyArm dist(Desktop, Core) from 201812 support 13/4MPix cameras for now.
 
in armbian(with 4.4 kernel) you need:
 - build and install a kernel with ov13xx driver(it's disabled now, also it missed a camera config) and rockchip ISP driver enabled;
 - install rkisp gstreamer driver to get accelerated access to Rk3399 ISP(Image Signal Processor - where CSI cameras connected, );
 - maybe few more things;
 
new 4.20 kernel(you can install it from armbian-config) create a /dev/video0 - it's not correct device for camera.
 
in next few days I will make some test, so will share some info here