ObjectMap's `find` method can get stuck in an infinite loop.

Part of my engine uses a Map to keep track of calls for a certain function.
```haxe
var list: Array;
var firstUpdates: Map;

function ME_StartCheck(): Void {
for (comp in list) {
if (!comp.Enabled) continue;
if (firstUpdates[comp]) continue;
comp.OnStart();
firstUpdates[comp] = true;
}
}
```

After enough calls the `find` method gets caught in an infinite loop thanks to `ckey` starting as zero and `_MNEXT(m,c)` also returning zero.
```cpp
_MSTATIC _MVAL_TYPE *_MNAME(find)( t_map *m, t_key key ) {
int c, ckey;
unsigned int hash;

if( !m->values ) return NULL;
hash = _MNAME(hash)(key);
ckey = hash % ((unsigned)m->ncells);
c = _MINDEX(m,ckey);
while( c >= 0 ) {
if( _MMATCH(c) )
return &m->values[c].value;
c = _MNEXT(m,c);
}
return NULL;
}
```

I'm not familiar enough with HashLink to come to a conclusion on how this happens. But the objects I store in the map are never iterated over or constantly changing. The map also isn't created in C, it is only interacted with via Haxe code.