--enable-build-20 : Build the Motif 2.0 compatible version of the lesstif libraries. --enable-build-21 : Also build the Motif 2.1 compatible versions. --disable-debug : Do not generate debugging information. --enable-production : Build the release version of the lesstif libraries. --disable-build-tests : Do not build the test/ tree (see Testing lesstif). --with-xdnd : Enable XDND Gnome compatibility support.