Finally were able to create a Gentoo system partition and build Cinelerra there.  There are 2 tars available and because gg was able to incorporate Gentoo into Xen, he will be able to build these monthly (at least for awhile).  They are at:
   https://cinelerra-gg.org/download/tars/cinelerra-5.1-gentoo-20200202.x86_64-static.txz
   https://cinelerra-gg.org/download/tars/cinelerra-5.1-gentoo-20200202.x86_64.txz
Standard tar install procedure as in the README.txt file in the download directory.