fix(library/unifier): memory violation, and missing set_conflict
fix(library/unifier): memory violation, and missing set_conflict

Signed-off-by: Leonardo de Moura <7610bae85f2b530654cc716772f1fe653373e892@microsoft.com>

soonhokong/lean,Kha/lean,avigad/lean,UlrikBuchholtz/lean,soonhokong/lean-windows,eigengrau/lean,sp3ctum/lean,dselsam/lean,leodemoura/lean,dselsam/lean,soonhokong/lean,fgdorais/lean,sp3ctum/lean,leanprover-community/lean,soonhokong/lean-osx,johoelzl/lean,soonhokong/lean,johoelzl/lean,c-cube/lean,c-cube/lean,soonhokong/lean-windows,eigengrau/lean,leodemoura/lean,htzh/lean,soonhokong/lean-windows,dselsam/lean,fpvandoorn/lean,rlewis1988/lean,fpvandoorn/lean2,Kha/lean,javra/lean,leanprover-community/lean,dselsam/lean,dselsam/lean,Kha/lean,digama0/lean,eigengrau/lean,avigad/lean,fpvandoorn/lean,leanprover/lean,leodemoura/lean,c-cube/lean,leodemoura/lean,UlrikBuchholtz/lean,digama0/lean,fpvandoorn/lean2,leanprover/lean,avigad/lean,leanprover/lean,Kha/lean,johoelzl/lean,fgdorais/lean,sp3ctum/lean,digama0/lean,digama0/lean,avigad/lean,leanprover-community/lean,sp3ctum/lean,fgdorais/lean,eigengrau/lean,fpvandoorn/lean,digama0/lean,fgdorais/lean,levnach/lean,dselsam/lean,soonhokong/lean-osx,soonhokong/lean,eigengrau/lean,htzh/lean,rlewis1988/lean,levnach/lean,soonhokong/lean-windows,soonhokong/lean-osx,levnach/lean,fpvandoorn/lean,UlrikBuchholtz/lean,fgdorais/lean,leanprover/lean,digama0/lean,fpvandoorn/lean2,leanprover-community/lean,UlrikBuchholtz/lean,fpvandoorn/lean,c-cube/lean,rlewis1988/lean,leanprover/lean,soonhokong/lean-osx,leanprover/lean,htzh/lean,levnach/lean,fpvandoorn/lean2,avigad/lean,sp3ctum/lean,htzh/lean,htzh/lean,javra/lean,fgdorais/lean,UlrikBuchholtz/lean,levnach/lean,fpvandoorn/lean,rlewis1988/lean,Kha/lean,javra/lean,soonhokong/lean,johoelzl/lean,c-cube/lean,leodemoura/lean,javra/lean,leanprover-community/lean,johoelzl/lean,Kha/lean,avigad/lean,rlewis1988/lean,fpvandoorn/lean2,leanprover-community/lean,soonhokong/lean-osx,leodemoura/lean,javra/lean,johoelzl/lean,rlewis1988/lean,soonhokong/lean-windows