Thanks!

The first 5 commits look good overall.
For the last one, I think there are a few confusions:

- native-inputs takes packages or origins, it does not take a lambda.

- To call a custom function from the builder, you need to include the
  module that defines it for the build system, e.g.

  (arguments
    `(#:modules ((gnu packages telephony)
                 ,@%gnu-build-system-modules)
      ...)

- In this particular case, you could even make a macro that is expanded
  at definition time, so that you would not even need to import the module.
  If you don't know how to write scheme macros, no need to go down this
  road for now.

But before fixing this issue, what are you trying to do exactly?
Do you intend to reuse this `jami-apply-dependency-patches' procedure
somewhere else?


On a different topic, to avoid sending patch archives in the future, you
could use a public repository clone of Guix.
There are a couple of free services out there, like sr.ht, maybe
gogs.io, etc.
This would make it smoother to track your progress and help you in the process.

-- 
Pierre Neidhardt
https://ambrevar.xyz/