libiberty build failure in Sept.1 egcs snapshot

[Jim Wilson]

	Towards the end of the build make moves into libraries/libiberty,...
	Now I noticed that $(srcdir)/libiberty exists as well.

./libiberty is compiled by the host compiler.  ./libraries/libiberty is
compiled by the target compiler.  In a native build, these are usually
(but not always) the same.  It isn't strictly necesary to have both when
they are the same, however, it is currently necessary to avoid build problems
that occur for targets that use multilib.  libstdc++ depends on libiberty,
so if libstdc++ is multilibbed then we must also multilib libiberty, and
the only way we can do that currently is to always force libiberty to be
compiled at least twice.

This problem can be worked around by using --disable-multilib.  If you
use this configure option, then libiberty will only be built once.
It does mean that you don't get any multilibbed libraries though, so it
isn't recommended for general use.

Jim