• Error messages from DBM::Deep now use the caller’s file name.
  They used incorrectly to use the name of the program ($0).
  
• begin_work now checks correctly to see whether the new transac-
  tion exceeds the number the file was created to support. Some-
  times it would allow a few more transactions, and then proceed
  to corrupt the database (RT#60903).
  
• The description of the file header in DBM::Deep::Internals has
  been brought up to date.