Simple questions, MAKE_ARGS in pkgtools.conf

[Nikolas Britton]

Lets say I have BATCH=yes (/etc/make.conf) and I have a port with a menu 
that turns on some flags i.e.:

OPTIONS=        DEBUG "Build a debugging image" off \
                LOGGING "Enable additional log messages" off \
                OPTIMIZED_CFLAGS "Enable some additional optimizations" 
off \
                XFT "Enable support for anti-aliased fonts" on \
                SMB "Enable smb:// URI support using gnomevfs" off

If I do something like the following:

MAKE_ARGS = {
'www/firefox' => 'WITH_OPTIMIZED_CFLAGS=yes CPUTYPE=p4',
'multimedia/gstreamer-*' => 'CPUTYPE=p2'
}

Will portupgrade only build the port with what I put in MAKE_ARGS or 
will it just append it to the ports config?
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Making this up in my head so I might not be giving the example I was 
thinking of:

Port Makefile:
OPTIONS= FOO "build with FOO" off

.if defined(WITHOUT_FOO)
CONFIGURE_ENV+= WITHOUT_FOO=yes
.endif # defined(WITHOUT_FOO)

Would I set it to WITHOUT_FOO=no?
-----------------------
Someone on this list once said that if you build a port with optional 
make options that freebsd will always remember those options and will 
rebuild the port with them if you have BATCH=yes, is this true and if so 
whats the point of MAKE_ARGS?
-----------------------
In summary I am not sure how to handle building ports with BATCH=yes and 
making sure my ports get built with the correct make options when 
upgrading and I don't know where the doc's are so I can learn about it.