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 nested10;

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

void main()
{
    int j = 3;
    void F()
    {
        int i = j;
        printf("F: i = %d, j = %d\n", i, j);
        void G()
        {
            printf("G: i = %d, j = %d\n", i, j);
            j += i;
        }
        G();
    }
    F();
    printf("6 = %d\n", j);
    assert(j == 6);
}