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 bug20;
extern(C) int printf(char*, ...);

void func(void delegate() dg)
{
    dg();
}

void main()
{
    int i = 42;
    void delegate() dg = {
        i++;
    };
    printf("i = %d\n",i);
    func(dg);
    printf("i = %d\n",i);
    assert(i == 43);
}