Remove a dead variable from ldmd. (It used to be used to pass an extra -help to ldc when no files were specified, but we handle that in ldc itself now)

module bug49;

struct S
{
    int i;
    long l;
}

void main()
{
    S s;
    s.i = 0x__FFFF_FF00;
    s.l = 0xFF00FF_FF00;
    s.i &= s.l;
}