Fixed ModuleInfo generation to no longer use the ModuleInfo class' default initializer for types/defaults, it's unsafe as initializers don't necesarily match the "formal" type. There might be explicit padding. Changed -g switch to emit DW_LANG_D debug info, make demangling work with a patched GDB, still more work to do for full support of D's Dwarf extensions. Added getNullValue helper method.

module mini.arrays20;

int[] foo()
{
    return [2,4,6];
}

int[] bar()
{
    return [1,3,5];
}

void main()
{
    auto a = foo();
    auto b = bar();
    assert(b[0] == 1);
    assert(a[0] == 2);
    assert(b[1] == 3);
    assert(a[1] == 4);
    assert(b[2] == 5);
    assert(a[2] == 6);
}