mk/flavours/validate.mk has

GhcStage2HcOpts    = -O -dcore-lint

GhcLibHcOpts       = -O -dcore-lint

How can I override these in my validate.mk?  E.g.

GhcLibHcOpts      += -ddebug-output

does not work.

Thanks. One should really be able to override anything.

Simon