------- Comment #5 from jakub at gcc dot gnu dot org 2010-09-03 07:30 ------- I think for -D and -U at least the canonicalization should be joined instead of separate, because that's how people are used to write these options (which doesn't mean the tools the driver invokes shouldn't be changed to handle both). And for -I- similarly.
-- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45499
