#pragma interface (was Re: ia64 c++ abi exception handling)

[Benjamin Kosnik]

These pragmas are removed in the current sources. There is no use of
pragma interface/implementation in the libstdc++-v3 source tree.

> Unfortunately, we have a major customer who relies on the #pragmas
> because one of their targets is i960-b.out.

Positions are pretty well staked out on this issue. Jason and Geoff
Keating seem to be the only advocates of extending this extension's
lifespan. 

I think it should be clearly marked as deprecated, especially if the
only reason it's around it to carry legacy code from a single client
for a chip that's officially dead. (gak: i960)

...especially if it's getting in the way of clear linkage
implementations, or (my pet peeve) a pre-compiled header solution.
Linkage is hairy enough as it is, why complicate otherwise rediculous
requirements with additional complexity? 

-benjamin