The goal is simply to get my raspberry Pi 4 running Ubuntu 20.04 (64 bit) and ROS1/Noetic to use a raspberry Pi Camera.
Now there are many pages devoted to this questions and I have tried them all. I have encountered the missing module meal. I have downloaded and rebuilt the raspicam_node directly from ubiquity Robotics web site. I have tried a lot of things. And I have been here before. In fact buried in my memory is that the problem was connected with 64 bit which is why I included it in my intro above.
So googling for an answer isn't going to work.
Most recently I noticed that there is something called "vc_hack" inside the raspicam_node package. Cd'ing to that directory followed by make clean; make install
made the mmal error go away only to be replaced now by a missing header file interface/vcos.h.
Do you know of a known-working-recently set of instructions or code to help me over this roadblock?