I think something like this patch can be applied to automated builds, where you
generally don't look into directories for debug, just want you binary package fast.

I was trying to build CinelerraGG from source in just ~700 Mb compressed btrfs image on
Live DVD from Linux Mint 18, 32-bit (from ~early 2016). With total 2Gb of memory
for my virtual machine. It worked after I disabled ffmpeg's debug symbols, programs,
and few other things in Cinelerra itself.

Feel free to adapt to your needs.

PS: what exactly this file in thirdparty/src does, I can't find reference to it?
-rw-r--r--  32600440  cimg-source.txz