MacPorts: Add an option to configure script

I am trying to install libguichan without allegro support, because allegro will not build on Snow Leopard.

It should be left out, the portfile has:

27  if {${os.platform} == "darwin" && (([variant_isset universal] && [string match *64* $universal_archs]) || (![variant_isset universal] &开发者_Go百科;& [string match *64 $build_arch]))} {
28      # allegro is not yet 64-bit compatible
29      depends_lib-delete port:allegro
30      configure.args-append --disable-allegro
31  }

But when I install it, it tries to build allegro. Is there any way I can get this functionality from the command line to install it?

The port: http://trac.macports.org/browser/trunk/dports/graphics/libguichan/Portfile

Problem was fixed by running sudo port -v selfupdate