If you've just downloaded the distribution from cvs, a:
$ autoreconf --install
builds up the building infrastructure (if you want to come back to a "cvs
status", go through the ./configure and then 'make extraclean').

If you've downloaded an official distribution, or already you've made the step
before, do a:
$ ./configure
(./configure --help to have a list of pertinent arguments, like
--disable-tuntap)
then:
$ make
and if you want:
$ make install


MACOS 10.3:
these extra tools must be installed first:
autoconf-2.59,automake-1.9,libtool-1.5.20