anchor.diff:      interface
           subroutine plstripd( id )
               use plplot_types
  +            implicit none
               integer(kind=plint) :: id
           end subroutine plstripd
       end interface
  
positive.code:     interface
          subroutine plsfci( fci )
              use plplot_types
              integer(kind=plunicode) :: fci
          end subroutine plsfci
      end interface
  
negative.code:     interface
          subroutine pladv( sub )
              use plplot_types
              implicit none
              integer(kind=plint) :: sub
          end subroutine pladv
      end interface
  