Debian install problems

Hello
I have looked in the forum, but do not see recent posts on Debian installs. A quick main question : Did anybody successfully installed OF on a recent Debian system? Which one?
I would love to install OF on my current Debian system ( which is AVL-MX, on a Debian Buster) but when running the install script I get the error :
Package gstreamer-app-0.10 was not found in the pkg-config search path. .
Perhaps you should add the directory containing `gstreamer-app-0.10.pc’
to the PKG_CONFIG_PATH environment variable ----
Not finding documentation to fix it unfortunately.
– there could be more problems after this, I would not know that. I have been away from OF for a few years, but would very much like to use this amazing tool a little bit again. If necessary I will just install a system somewhere on which it compiles and runs.

Thanks very much in advance
Vilbjørg

problems by install dependencies:

Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
libopencv-dev : Depends: libopencv-calib3d-dev (= 3.2.0+dfsg-6) but it is not going to be installed
Depends: libopencv-contrib-dev (= 3.2.0+dfsg-6) but it is not going to be installed
Depends: libopencv-features2d-dev (= 3.2.0+dfsg-6) but it is not going to be installed
Depends: libopencv-highgui-dev (= 3.2.0+dfsg-6) but it is not going to be installed
Depends: libopencv-objdetect-dev (= 3.2.0+dfsg-6) but it is not going to be installed
Depends: libopencv-stitching-dev (= 3.2.0+dfsg-6) but it is not going to be installed
Depends: libopencv-superres-dev (= 3.2.0+dfsg-6) but it is not going to be installed
Depends: libopencv-videoio-dev (= 3.2.0+dfsg-6) but it is not going to be installed
Depends: libopencv-videostab-dev (= 3.2.0+dfsg-6) but it is not going to be installed
libxxf86vm-dev : Depends: x11proto-xf86vidmode-dev (>= 2.2.99.1)
E: Unable to correct problems, you have held broken packages.
error installing dependencies, there could be an error with your internet connection
if the error persists, please report an issue in github: http://github.com/openframeworks/openFrameworks/issues

YES, I have OF compiled and working. It is on AVL 2020 (AVLinux May 2020) It is basically a freshly installed system, with no modifications, also not to sources.list. I have compiled and run a few examples, so I think it is good. I guess this thread can be standing up if anyone should arrive with the same question.
Thanks for keeping up the forum anyway.
Vilbjørg