Reintroduced pre-evaluation of when-condition.  This results in a big speedup if the condition is (partially) true, at the cost of a marginal slowdown otherwise.
Reintroduced pre-evaluation of when-condition.  This results in a big
speedup if the condition is (partially) true, at the cost of a marginal
slowdown otherwise.

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