Removed some checks for abstract llvm types that were too strict, a 'opaque* null' is a valid initializer... when structs in D can be just a forward reference.

module mini.norun_debug4;

void main()
{
    char c = 'c';
    wchar wc = 'w';
    dchar dc = 'd';

    int* fail;
    *fail = 32;
}