Makefile: add 'discard' target, to discard changes to checked-in generated files. This is useful to avoid conflicts when merging / rebasing / doing 'git stash pop'.
Makefile: add 'discard' target, to discard changes to checked-in generated files.
This is useful to avoid conflicts when merging / rebasing / doing 'git stash pop'.

Signed-off-by: Daira Hopwood <cd7d43d5556a38ce626d53826fddc46adc597539@jacaranda.org>

zcash/zips,zcash/zips,zcash/zips,zcash/zips