Thank you rodw. I installed
libboost-python-dev but I have the same result.
But in the mean time I compared the differences between working Desktop and RPi4 with problems.
Seems that the
boost_python is in the wrong place or the wrong version.
In the attached photos i put the logs from PC & RPi4 (Left column is PC log and Right column is RPi4)
At line 86(PC) and 80(RPi) it states "checking whether the Boost::Python library is available... yes" but at line 88(PC) 83(RPi) differences
begin to appear.