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 arrays4;

void main()
{
    int[] arr;
    arr ~= 3;
    assert(arr.length == 1);
    assert(arr[0] == 3);
    arr ~= 5;
    assert(arr.length == 2);
    assert(arr[0] == 3);
    assert(arr[1] == 5);
}