always used, thus we don't need any more the Karatsuba and Toom-Cook code.
At some point in the future we should be able to rely on a separate library
as FLINT for the polynomial multiplication in (Z/nZ)[x].


git-svn-id: svn://scm.gforge.inria.fr/svnroot/ecm/trunk@1978 404564d9-a503-0410-82bf-e18ce2cf3989