Mostly rewrite debug info generation in terms of llvm/Analysis/DebugInfo.h. Add getCompilationModule to Dsymbol and fix template compile unit decision code. Runtime compiles with -g again.

interface IN
{
    void func();
}
abstract class AC
{
    abstract void func();
    long ll;
}
class C : AC
{
    void func()
    {
    }
}

void main()
{
    scope c = new C;
}