So I tried to build FreeCAD from git and get several build errors related to vtk.
Not sure exactly what should happen but it looks like vtk7 is misscompiled/configured.
if we concentrate on /usr/bin/vtkParseOGLExt-7.1 that do not exist in ubuntu 20.04 it does in ubuntu 19.04 there is several other files that is missing also.
https://packages.ubuntu.com/search?suite=eoan&arch=any&mode=filename&searchon=contents&keywords=vtkParseOGLExt
------------------------
errors
-- The imported target "vtkParseOGLExt" references the file
"/usr/bin/vtkParseOGLExt-7.1"
but this file does not exist. Possible reasons include:
* The file was deleted, renamed, or moved to another location.
* An install or uninstall procedure did not complete successfully.
* The installation package was faulty and contained
"/usr/lib/cmake/vtk-7.1/VTKTargets.cmake"
but not all the files it references.
-- The imported target "vtkRenderingPythonTkWidgets" references the file
"/usr/lib/x86_64-linux-gnu/libvtkRenderingPythonTkWidgets.so"
but this file does not exist. Possible reasons include:
* The file was deleted, renamed, or moved to another location.
* An install or uninstall procedure did not complete successfully.
* The installation package was faulty and contained
"/usr/lib/cmake/vtk-7.1/VTKTargets.cmake"
but not all the files it references.
-- The imported target "vtk" references the file
"/usr/bin/vtk"
but this file does not exist. Possible reasons include:
* The file was deleted, renamed, or moved to another location.
* An install or uninstall procedure did not complete successfully.
* The installation package was faulty and contained
"/usr/lib/cmake/vtk-7.1/VTKTargets.cmake"
but not all the files it references.
-- The imported target "pvtk" references the file
"/usr/bin/pvtk"
but this file does not exist. Possible reasons include:
* The file was deleted, renamed, or moved to another location.
* An install or uninstall procedure did not complete successfully.
* The installation package was faulty and contained
"/usr/lib/cmake/vtk-7.1/VTKTargets.cmake"
but not all the files it references.
-- VTK components: vtkCommonCore;vtkCommonDataModel;vtkFiltersVerdict;vtkIOXML;vtkFiltersCore;vtkFiltersGeneral;vtkIOLegacy;vtkFiltersExtraction;vtkFiltersSources;vtkFiltersGeometry;vtkIOMPIParallel;vtkParallelMPI;vtkhdf5;vtkFiltersParallelDIY2;vtkRenderingCore;vtkInteractionStyle;vtkRenderingFreeType;vtkRenderingOpenGL2
Same problem here, trying to build FreeCAD for 20.04.