Use the simplified genscripts.sh and set the cross-compiled library

Use the simplified genscripts.sh and set the cross-compiled library
directory to /usr/cross/${MACHINE_ARCH}-freebsdelf/usr/lib so that
the cross tools behave the same way that the host versions do. When
building cross tools, Cygnus doesn't set the default library directory.
This doesn't suit FreeBSD IMHO.

Add WinNT emulation support too. You only get this if you've set
BINUTILSDISTDIR because the contrib/binutils repository doesn't
contain the required sources.