[svn r354] Fix the regressions between [346] and [353] by making constructors and destructors outside classes fatal errors. Fix tests makefile and add minimize to gc.d.

module c;

void main()
{
    ushort a = 0xFFF0;
    ushort b = 0x0FFF;
    auto t = a & b;
    a &= b;
    assert(t == a);
}