including source from include files

I have a number of procedures each in their own file of the form NAME.inc which are all components of a module, that includes them all.
I can specify the include directories with include: and the documentation for the routines appears to be correct (a lot were missing without using include: ). I get the source to show if I add "inc" as an extension, but then I get duplicates, one from the INCLUDE in the module, one from the .inc file and the diagrams become confused). So it does not look like duplicates are reduced before processing. I wanted the include files to be able to show the source with the procedure documentation. Is there a combination that would work for this? I have not found an option combination that does what I want. I want to not use a suffix like .f90 for the .inc files as that confuses the build system I am using, at least using the current file layout. I am placing this as an issue instead of a usage question as I believe there is not a way to do it currently, but that if the
files were reduced to get rid of the duplicates it might work.

The project I am trying this with can be found at

https://github.com/jacobwilliams/odepack