jdfgen generates bad SRCFILE section for classes without 'SourceFile' attribute

The jdfgen utility (template file generator) generates such SRCFILE section
for classes without the 'SourceFile' attribute, which breaks the rpgMain
utility (report generator) :
SRCFILE: Source file UNKNOWED

After trying to generate a report for such class, rpgMain outputs the
error message "String index out of range: -1" followed by usage information,
and terminates.