Thank you dkulp..I thought also supported 18.04, did a clean install of Ubuntu 19.04 on my xmas-pc, installed all libraries listed on the Readme file, cloned xLights.. tried to compile...still got errors, read more about the installation of wxWidgets found that there is choice with gtk2 or gtk3, made a change in xLights Makefile to configure wxWidgets with-gtk=3 instead of gkt=2 and was able to compile xLights 2020.12 in Ubuntu 19.04.
Thank you again for pointing that.