To try whether I am able to fix it, I copied the lib from the same build into a path known by LD_LIBRARY_PATH. It fixed
Code
tvheadend: error while loading shared libraries: libhdhomerun.so: cannot open shared object file: No such file or directory
but now I get
Code
tvheadend: error while loading shared libraries: libx265.so.199: cannot open shared object file: No such file or directory
and I can't find this lib in my current build.
After creating the tvheadend42 addon the lib was built. I copied it into some LD_LIBRARY_PATH configured folder and now everything works again.