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.

module tangotests.volatile1;

import tango.stdc.stdlib;

void main()
{
    int var = rand();
    {
        int i = var;
        volatile;
        int j = i;
    }
}