3.3 PATCH: Add --with-sysroot support

[Gabriel Dos Reis]

"H. J. Lu" <hjl@lucon.org> writes:

| Since I need a stable compile with --with-sysroot support, I backported
| it to gcc 3.3.

I understand you want sysroot support, but I don't see why we want or
need that for 3.3.x.  Would you mind elaborating?
(That is not an argumentative question).  
I would need input from one of our build system maintainers. 

-- Gaby