Installed location of 'as' for cross targets (--enable-targets)

[Carlos O'Donell]

> The behaviour of the configure script is in flux, and may be
> permanently changing.  When you specify --host, the gas configure
> script now thinks you are building a cross-assembler, even when --host
> and --build are the same.

Knowing it's in flux is half the battle.
 
> The fix may be to only specify --build.  But then that may not work at
> the top level.  Not sure.

Thanks.

c.