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 typeinfo7;
extern(C) int printf(char*, ...);
int func(long)
{
    return 0;
}

void main()
{
    auto ti = typeid(typeof(func));
    auto s = ti.toString;
    printf("%.*s\n", s.length, s.ptr);
    assert(s == "int()");
}