Remove an old workaround that was kept around for ABI-compatibility on x86-64 between different LLVM versions. This means LLVM r67588 is required if you want to compile for x86-64, otherwise the backend will assert when you try to return e.g. struct { int i; char c; } from a function. (In particular, this is no longer compatible with LLVM 2.5) It also means that any code returning small structs on x86-64 will probably need to be recompiled in order to be linkable to code compiled with this change.

module aa1;

void main()
{
    int[int] aai;
    assert(aai is null);
    aai[0] = 52;
    assert(aai !is null);
    int i = aai[0];
    assert(i == 52);
    aai[32] = 123;
    int j = aai[32];
    assert(i == 52);
    assert(j == 123);
}