Hi Maxime,

Here is the version of the GPG package which I intended to send in the
first place with the verbiage about GPG4WIN removed per your suggestion.

8<------------------------------------------------------------------------------------
(define-public r-gpg
  (package
    (name "r-gpg")
    (version "1.2.6")
    (source
     (origin
       (method url-fetch)
       (uri (cran-uri "gpg" version))
       (sha256
        (base32 "17rvi3qff2kanqr3g20dzhn48bfh5sv57g0wsamndzcif7rhjhby"))))
    (properties `((upstream-name . "gpg")))
    (build-system r-build-system)
    (propagated-inputs (list r-askpass r-curl))
    (native-inputs (list pkg-config r-knitr gpgme gnupg))
    (home-page "https://github.com/jeroen/gpg")
    (synopsis "GNU Privacy Guard for R")
    (description
     "Bindings to GnuPG for working with OpenGPG (RFC4880) cryptographic methods.
Includes utilities for public key encryption, creating and verifying digital
signatures, and managing your local keyring.  Some functionality depends on the
version of GnuPG that is installed on the system.")
    (license license:expat)))
------------------------------------------------------------------------------------>8

I have also attached a new patch.

Kyle