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.

struct Color {
    uint c;

}

struct Vertex {
    double x, y;
    Color c;
    static Vertex opCall(double x, double y, Color c) {
        Vertex ret;
        ret.x = x;
        ret.y = y;
        ret.c = c;
        return ret;
    }
}

void main() {
    Color c = {0xffffffff};

    auto v = Vertex(1, 5, c);

    assert(v.x == 1 && v.y == 5); // passes
    assert(v.c.c == 0xffffffff);  // fails in LDC
}