make validation depend on clpb_validation flag
make validation depend on clpb_validation flag

jn7163/swipl-devel,mndrix/swipl-devel,edechter/swipl-devel,koryonik/swipl-devel,koryonik/swipl-devel,koryonik/swipl-devel,jn7163/swipl-devel,edechter/swipl-devel,koryonik/swipl-devel,mndrix/swipl-devel,mndrix/swipl-devel,mndrix/swipl-devel,edechter/swipl-devel,jn7163/swipl-devel,edechter/swipl-devel,koryonik/swipl-devel,jn7163/swipl-devel,mndrix/swipl-devel,jn7163/swipl-devel,edechter/swipl-devel