make prefix=xxx install no longer working on main line

[Arnaud Charlet]

It is no longer possible to do a

make prefix=xxx install

where xxx is different from the prefix used when configuring GCC.

I suspect this is due to the following change:

2004-04-26  Paolo Bonzini  <bonzini@gnu.org>

	* Makefile.def (flags_to_pass): Remove *dir variables that
	are passed to the modules via TOPLEVEL_CONFIGURE_ARGUMENTS,
	as well as prefix and exec_prefix.
	* Makefile.in: Regenerate.

Paolo, could you investigate ? Thanks.

Arno