>Where are MACHINE_ARCH and LOWER_ARCH defined?

MACHINE_ARCH comes from uname, the environment or the command line.

bmake allows a forced MACHINE_ARCH to be built in - for cases where uname
doesn't provide a value - or its wrong.  But you can always override via
the enviornment or command line.

>Anyways, my problem is my MACHINE_ARCH is i686, but some Makefiles only
>check for i386.

This is common on linux too - uname -m outputs i686 etc, uname -p outputs
"unknown" which is particularly lame.  The JDK and most of my stuff
fold i?86 to i386 (who cares about anything else?) and 
"unknown" -> i386 too if MACHINE is i?86.

--sjg