I recently had a small problem with documenting a Fortran program:
Subroutine tst(ExternalName)
  character*(*) ExternalName
end

The result Doxygen page is:
  Function Documentation
  subroutine tst ( ExternalName   )  
Instead of the expected:
  Function Documentation
  subroutine tst ( character*(*)   ExternalName )  

Some small investigations lead to the fact that the lexical scanner (fortranscanner.l) does recognize the reserved word External in the argument list and does not recognizes that it is not the word ExternalName.
Changing the word to MyExternalName also gives the correct output, so it looks like that the end of the word is nor recognized correctly.
I have hardly any experience with lex (and yacc) but shouldn't read the line (222) with the ATTR_SPEC definition read EXTERNAL\> instead of EXTERNAL for this keyword. The same accounts of course for all other reserved names.