[Dune] how to make ctags file?

[Yufei Cao]

Dear Dune Developers,

I knew that Dune can generate ctags file from  'The DUNE Buildsystem HOWTO'.
And I have tried the following command 

'./dune-common-1.0beta5/bin/dunecontrol make ctags'

But many seperate tags files are generated in all directories of Dune. How to 
get only one tags file with all the information recursively through the 
directories? Then I can use this tags file for vi. Thank you !

Best regards,
Yufei