Unify --with-sysroot defaults

[Nick Clifton]

Hi Alexandre,

> Index: ld/ChangeLog
> from  Alexandre Oliva  <aoliva@redhat.com>
> 
> 	* configure.in (TARGET_SYSTEM_ROOT): Set default to
> 	${exec_prefix}/${target_alias}/sys-root.  Match explicit
> 	'${exec_prefix}' (in addition to the expansion thereof) as
> 	relocatable.
> 	* configure: Rebuilt.

Approved - please apply.

Cheers
        Nick