How to diff just the source files?

Question

I have two almost similar source code trees, but do not have access to the source code repository so I am stuck with release packages that contain also test reports, documentation, binaries etc.

the diff command only support --exclude, but I would like to do something like diff -wbur --include='*.c,*.h' tree1 tree2

I know that this question is somewhat related, but does not really address my issue.

Bonus points for ignoring change blocks that are completely in C comments :)

Answer 1

Little modification to a result from google helped, in tree1 did find . -name '*.[ch]' -exec diff -wibu {} ../tree2/{} \;