[PATCH] add __attribute__ ((designated_init))

[Tom Tromey]

Joseph> Is there a reason someone using the attribute might not want the
Joseph> warning?  That is, why isn't -Wdesignated-init enabled by
Joseph> default, given that it's only relevant to people using an
Joseph> attribute whose sole function relates to the warning?

In making this change, I also removed the new option from -Wall.
It seemed like that would be the best approach; but I thought I'd note
it just to be sure.

Tom