The first run of 'guix pull' fails. The log[1] includes the error:
Starting download of /gnu/store/n7hw4dgm9qh1ihhb13jf5a1ll0wgf6ns-pkg-config-0.28.tar.gz
;;; Failed to autoload make-session in (gnutls):
;;; ERROR: missing interface for module (gnutls)
ERROR: In procedure module-lookup: Unbound variable: make-session