GCC 4.0 vs. 3.5

[Zack Weinberg]

I continue to believe that major version number increments should only
happen when backward compatibility is deliberately broken, and not in
a way that users have been acclimatized to, e.g. the continual
revision of the C++ abi doesn't count.

Incorporating the new Fortran front end is a big enough change - but
only for users of Fortran.  Shipping an "f90" command and not an "f77"
command is sufficient advertisement of that fact - and we may not have
to do that, if we can make the new front end sufficiently backward
compatible to handle Fortran 77, which I hope we do.

Frankly, if a change were on the table that *would* justify bumping
the major version number of the entire compiler collection, I expect
it would be shouted down in short order.

I only countenanced the 2->3 bump because it was necessary to make
clear to users that the forked development effort was over (and
because the internal version numbers for EGCS were chosen incorrectly,
such that we were up a creek).  The 1->2 bump was well before my time
so I won't comment on it.

zw