I’m not exactly sure which source file do you mean, but while you are waiting for your code to compile every second of unnecessary waiting counts, so I would much prefer implementing one an extra mechanism in the build process (e.g., generate and check a timestamp) if that saves 5-10 seconds for each build for each developer.
Maybe the wrapping process in VTK proper is already quite complex, but the vtkWrapHierarchy macro in vtkAddon is still quite straightforward.
Thank you! Reverting the original commit that removed the timestamp in VTK8 - reverting it has fixed the problem!
So, we can now just focus on making vtkWrapHierarchy faster.