A quick and dirty solution for chmod -R aw these folders, so svn cannot delete them.
However, I would have thought that if it does not regenerate, it should be under version control, and if it regenerates, does it not matter?
Or recompilation for everyone will be prohibitively long.
Please note that it will only delete them for the first time, so while you protect files with the first update, you should be fine.
EDIT: or a classic copy of the copy; copy it after upgrade. "
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