Fix stack overflow at travis when using clang++ 3.3 in debug mode
Fix stack overflow at travis when using clang++ 3.3 in debug mode

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

fpvandoorn/lean,leanprover-community/lean,johoelzl/lean,leanprover-community/lean,leanprover/lean,dselsam/lean,fgdorais/lean,soonhokong/lean-osx,fpvandoorn/lean2,soonhokong/lean,dselsam/lean,javra/lean,fgdorais/lean,fpvandoorn/lean,leanprover-community/lean,javra/lean,leanprover/lean,UlrikBuchholtz/lean,rlewis1988/lean,fpvandoorn/lean2,soonhokong/lean,johoelzl/lean,levnach/lean,htzh/lean,codyroux/lean0.1,leanprover-community/lean,fgdorais/lean,eigengrau/lean,Kha/lean,rlewis1988/lean,eigengrau/lean,Kha/lean,avigad/lean,soonhokong/travis_test,leanprover/lean,soonhokong/lean-windows,digama0/lean,UlrikBuchholtz/lean,soonhokong/travis_test,digama0/lean,sp3ctum/lean,johoelzl/lean,soonhokong/lean-windows,eigengrau/lean,dselsam/lean,levnach/lean,soonhokong/travis_test,avigad/lean,htzh/lean,leanprover-community/lean,htzh/lean,digama0/lean,fpvandoorn/lean,UlrikBuchholtz/lean,sp3ctum/lean,codyroux/lean0.1,javra/lean,levnach/lean,soonhokong/lean-windows,Kha/lean,c-cube/lean,fpvandoorn/lean2,digama0/lean,Kha/lean,c-cube/lean,leanprover-community/lean,fpvandoorn/lean,c-cube/lean,eigengrau/lean,javra/lean,levnach/lean,javra/lean,soonhokong/lean,fgdorais/lean,soonhokong/lean,soonhokong/travis_test,codyroux/lean0.1,soonhokong/lean-osx,rlewis1988/lean,leodemoura/lean,eigengrau/lean,dselsam/lean,fpvandoorn/lean2,Kha/lean,avigad/lean,sp3ctum/lean,fgdorais/lean,UlrikBuchholtz/lean,soonhokong/lean-osx,fpvandoorn/lean2,leanprover/lean,fpvandoorn/lean,avigad/lean,johoelzl/lean,fgdorais/lean,htzh/lean,soonhokong/lean,johoelzl/lean,dselsam/lean,leodemoura/lean,digama0/lean,johoelzl/lean,rlewis1988/lean,Kha/lean,avigad/lean,rlewis1988/lean,sp3ctum/lean,dselsam/lean,sp3ctum/lean,rlewis1988/lean,leodemoura/lean,leanprover/lean,codyroux/lean0.1,leodemoura/lean,digama0/lean,leanprover/lean,UlrikBuchholtz/lean,soonhokong/lean-osx,soonhokong/lean-windows,soonhokong/lean-windows,levnach/lean,leodemoura/lean,leodemoura/lean,fpvandoorn/lean,htzh/lean,soonhokong/lean-osx,c-cube/lean,c-cube/lean,avigad/lean