macro debugging info: emit correct line number for #inclusions

[David Edelsohn]

>>>>> Neil Booth writes:

Neil> That's great for 3.2.  Is this a regression in any sense against 2.95 or
Neil> 3.0?  If so it can go in 3.1 too.

	The new GCC development methodology is not just fixing regressions
relative to earlier releases but relative to functionality in earlier
stages of the development process for the current release.  If a patch
caused a regression and was not noticed until now, we still should fix it
for the release.

	When originally checked in to GCC 3.1, this functionality worked.
If some patch broke the improved debugging information, it is a prime
candidate to be fixed on the branch.

David