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.

interface Iin
{
    void[] read(size_t n);
}

interface Iout
{
    size_t write(void[] d);
}

class C : Iin
{
    void[] read(size_t n)
    {
        return null;
    }

    size_t write(void[] d)
    {
        return 0;
    }
}

void main()
{
    scope c = new C;
}