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 nested12;

extern(C) int printf(char*, ...);

void main()
{
    func();
}

void func()
{
    void a(int i)
    {
        printf("%d\n", i);
    }

    void b()
    {
        a(42);
    }

    b();
}