these files really use overflow facilities:

    gbring.o
    imonorder.o
    matrix-kbasis.o
    matrix.o
    monoid.o
    monorder.o
    overflow.o
    polyring.o
    varpower.o

these files depends on overflow.hpp

    CC.o
    CCC.o
    Eschreyer.o
    GF.o
    QQ.o
    RR.o
    RRR.o
    ZZ.o
    ZZp.o
    comp-gb-declared.o
    comp-gb.o
    comp-res.o
    debug.o
    frac.o
    freemod.o
    gb-default.o
    gb-homog2.o
    gb-sugarless.o
    gb-toric.o
    gbring.o
    gbweight.o
    imonorder.o
    matrix-kbasis.o
    matrix.o
    monoid.o
    monorder.o
    montable.o
    ntuple.o
    overflow.o
    polyring.o
    qring.o
    reducedgb-ZZ.o
    reducedgb-field-local.o
    reducedgb-field.o
    reducedgb.o
    res-a2-gb.o
    res-a2.o
    schorder.o
    skewpoly.o
    solvable.o
    spair.o
    varpower.o
    weylalg.o
    x-gb.o
    x-mat.o
    x-relem.o
