Patch to enable -Werror [take 2]

[David Edelsohn]

>>>>> Kaveh R Ghazi writes:

Kaveh> Though I think tying -Werror to two flags could get confusing,
Kaveh> especially when both are used together.  I would prefer to just rely
Kaveh> on the one flag (--disable-werror), and change the default when we
Kaveh> branch and get close to a release like we do for the "checking"
Kaveh> settings.  (This would still achieve your criteria for end-users.)

Kaveh> Does this arrangement sufficiently address your concerns?

	Yes, turning off -Werror on release branches is equivalent and
fine. 

	We need to document this someplace.  I note that checking and
-fno-common are enabled on the gcc-3_3-branch at the moment.

David