I have found that when building the Paraview Gitlab Master Build on Linux, that
three symbolic links are missing from the Superbuild/install bin directory
ln -s python3 python
ln -s python3-config python-config
ln -s pydoc3 pydoc
The install of the osmesa version (and probably other versions) fails when it can’t find python or python-config (I am not sure if it fails on missing pydoc, but I wanted to be complete).
The install completes if these three symbolic links are made and the superbuild script is attempted to be made again.