Can't compile LSR #1000 with 2.25.4

[Werner LEMBERG]

After inserting a version statement and running `convert-ly` on

  http://lsr.di.unimi.it/LSR/Item?id=1000

I get this ominous error:

```
init.ly:64:2: error: Guile signaled an error for the expression beginning here
#
 (let ((book-handler (if (defined? 'default-toplevel-book-handler)
In procedure cadddr: Wrong type (expecting pair): ()
```

Any idea how this can be fixed?


    Werner