Re-apply [1346], which was reverted in [1348], now that padding should no longer be a problem. As noted before, this will break ABI-compatibility on x86-64, so recompile old code before linking with newly-compiled code if you're on x86-64. As an added bonus, I actually tested it this time :).

#ifndef LDC_GEN_AA_H
#define LDC_GEN_AA_H

DValue* DtoAAIndex(Loc& loc, Type* type, DValue* aa, DValue* key, bool lvalue);
DValue* DtoAAIn(Loc& loc, Type* type, DValue* aa, DValue* key);
void DtoAARemove(Loc& loc, DValue* aa, DValue* key);

#endif // LDC_GEN_AA_H