Bug or typo in qlcpd.f

This line:

```fortran
* kmax.lt.0.or.(kmax.gt.0.and.maxg.le.1).or.tol.le.D0)then
```

Is referencing `D0` which is not a variable that has been given a value. I think it's a typo and should be `0.0D0` maybe:

```fortran
* kmax.lt.0.or.(kmax.gt.0.and.maxg.le.1).or.tol.le.0.0D0)then
```

Open qlcpd.f and inspect the condition containing tol.le.D0. Confirm whether D0 is an uninitialized or undefined reference and whether the proposed zero literal matches the intended threshold. Done means the condition uses the intended value and the Fortran library still builds successfully.

Written by the indexing model from the issue text.