Andrew, I find it scary too so I just do these steps manually after I finish the standard build:
1) go to wherever you have the directory of cinelerra-5.1
2) mkdir /tmp/AppDir
3) mkdir /tmp/AppDir/usr
4) cp -r bin /tmp/AppDir/usr
5) cd /tmp
6) run linuxdeploy from where it exists (in my case shown below, it is at /proj/appimage:
/proj/appimage/linuxdeploy-x86_64.AppImage --appdir=AppDir -o appimage -d /tmp/AppDir/usr/bin/applications/cin.desktop -i /tmp/AppDir/usr/bin/pixmaps/cin.svg -e /tmp/AppDir/usr/bin/cin -e /tmp/AppDir/usr/bin/mpeg2enc -e /tmp/AppDir/usr/bin/mplex -e /tmp/AppDir/usr/bin/hveg2enc -e /tmp/AppDir/usr/bin/lv2ui -e /tmp/AppDir/usr/bin/bdwrite -e /tmp/AppDir/usr/bin/zmpeg3toc -e /tmp/AppDir/usr/bin/zmpeg3show -e /tmp/AppDir/usr/bin/zmpeg3cat -e /tmp/AppDir/usr/bin/zmpeg3ifochk -e /tmp/AppDir/usr/bin/zmpeg3cc2txt -e /tmp/AppDir/usr/bin/mplexlo 2>&1 | tee appimage.log
Then there will be the file /tmp/cin-x86_64.AppImage which you can move to a non-temporary place