[rfc] using --with-sysroot for native builds

[Alan Modra]

On Thu, Oct 28, 2010 at 05:23:23PM +0200, Matthias Klose wrote:
> currently the --sysroot option for ld is only available if binutils
> is configured --with-sysroot=<...>.  My use case for using sysroots
> for native builds is having multiple chroots for different releases
> of an OS available for testing, and not having to install a new
> compiler/linker in the chroot itself. This basically works when
> configuring --with-sysroot=/, but then libraries are searched in //
> instead of /.
> 
> The following patch makes the --sysroot option available to ld
> independently of the configure option (making ld.bfd and ld.gold
> consistent), and avoids the extra slash prefix.

I think this should only be made available when native.  That's even
what you said above and in $subject, but your patch makes a cross
linker accept --sysroot.  Cross-linkers configured without a sysroot
will not search the usual directories.

-- 
Alan Modra
Australia Development Lab, IBM