Etc/make.conf

The file /etc/make.conf specifies all the defaults that make should use when building programs. Any changes in here will reflect globally, and specific changes can be very handy if you're going to be using the same options on a lot of builds. For example, adding

WITHOUT_X11= yes

to your make.conf will mean that if a port that you're building can be made without X11 options, it will be -- very handy for a headless_server.

Following the tip from [this page], I added the lines

SUP_UPDATE=yes
SUP= /usr/local/bin/cvsup
SUPFLAGS= -g -L 2
SUPHOST= cvsupX.us.freebsd.org 
SUPFILE= /usr/share/examples/cvsup/standard-supfile
PORTSSUPFILE= /usr/share/examples/cvsup/ports-supfile

to my make.conf, I was able to go into /usr/ports and type in

# make update

and update all my ports. Likewise, I can go into /usr/src and run the same command and update all my system sources.

You can see what options are available to you in /usr/share/examples/etc/defaults/make.conf

Note that you can also set compiler settings (for you Gentoo Linux expatriates) and CPU architecture in make.conf.