[patch,doc] Add target specific installation notes for Mingw32

[NightStrike]

On 1/31/08, Gerald Pfeifer <gerald@pfeifer.com> wrote:
> On Thu, 31 Jan 2008, FX wrote:
> > I supposed it's a very good time to review and modify our
> > target-specific installation notes. Here is a patch I propose to
> > document the few catches you need to know in order to build GCC on
> > mingw32. Tested with make info, html and pdf. OK to commit?
>
> Looks good to my eyes, though it would be nice to have someone more
> familiar with MinGW to review this as well.

Why is "with-gnu-as" and "with-gnu-ld" required to build the compiler?
 I've never used those options to build it on mingw...