support more than one architecture at a time, build as from the
default for the host and if CROSS_TOOLS defines other architectures,
build them as as_${arch}
support building it for variant architectures. It was already
becoming clear that the former structure was too rigid and didn't
scale well.
The usual sort of makefile magic arranges to .include an architecture
specific makefile "Makefile.${MACHINE_ARCH}" in each directory
where it exists. Also, sources will be found in each subdirectory
"${MACHINE_ARCH}" that exists. This is all taken care of automatically
by the top level "Makefile.inc0".
This all seems to work right for the i386 now. I have also converted
those alpha pieces already present to the new schema as best I
could.
Also: change the BINDIR on the i386 to /usr/libexec/elf for "ar"
and "ranlib". They are not object format independent enough to
put into /usr/bin.
