undo of
undo of

2009/02/05 - boncz: MonetDB/src/gdk/gdk_heap.mx,1.108
- make large allocs fall back again on mmap

which accidently went wrong;
proper fix that contains only yhe intended changes
will follow soon

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb