Hello Guix,

A long time ago I've noticed some problems with guix.el when installing
Guile from Guix.  My setup Guix 0.8.3 built from the tarball and
installed ontop of Debian 8 in the /usr/local prefix (nothing fancy :)).
At this state everything works fine, guix.el included!

First for Guix to be useful I change my paths to choose
"$HOME/.guix-profile/...", then I install Guile in my profile, and
eventually when I launch the emacs interface, Guix yells at me.

--8<---------------cut here---------------start------------->8---
Backtrace:
In guix/derivations.scm:
  19: 19 [#<procedure 13edac0 ()>]
In ice-9/boot-9.scm:
2951: 18 [define-module* (guix derivations) #:filename ...]
2926: 17 [resolve-imports (((srfi srfi-1)) ((srfi srfi-9)) ((srfi srfi-9 gnu)) ...)]
2864: 16 [resolve-interface (guix hash) #:select ...]
2789: 15 [#<procedure e19880 at ice-9/boot-9.scm:2777:4 (name #:optional autoload version #:key ensure)> # ...]
3065: 14 [try-module-autoload (guix hash) #f]
2401: 13 [save-module-excursion #<procedure 177b270 at ice-9/boot-9.scm:3066:17 ()>]
3085: 12 [#<procedure 177b270 at ice-9/boot-9.scm:3066:17 ()>]
In unknown file:
   ?: 11 [primitive-load-path "guix/hash" ...]
In guix/hash.scm:
  19: 10 [#<procedure 177f2e0 ()>]
In ice-9/boot-9.scm:
2951: 9 [define-module* (guix hash) #:filename ...]
2926: 8 [resolve-imports ((#) (#) (#) (#) ...)]
2864: 7 [resolve-interface (guix gcrypt) #:select ...]
2789: 6 [#<procedure e19880 at ice-9/boot-9.scm:2777:4 (name #:optional autoload version #:key ensure)> # ...]
3065: 5 [try-module-autoload (guix gcrypt) #f]
2401: 4 [save-module-excursion #<procedure 177b000 at ice-9/boot-9.scm:3066:17 ()>]
3085: 3 [#<procedure 177b000 at ice-9/boot-9.scm:3066:17 ()>]
In unknown file:
   ?: 2 [primitive-load-path "guix/gcrypt" ...]
In guix/gcrypt.scm:
  33: 1 [#<procedure 1784720 ()>]
In unknown file:
   ?: 0 [dynamic-link "libgcrypt"]

ERROR: In procedure dynamic-link:
ERROR: In procedure dynamic-link: file: "libgcrypt", message: "file not found"
--8<---------------cut here---------------end--------------->8---

what is happening is that Guix uses Guile installed from Guix but is
unable to dynamically link with the Libgcrypt from debian or even with
the Libgcrypt installed from guix in my profile.

So my current fix is to add (setq guix-guile-program "/usr/bin/guile")
to my .emacs file, then everything works fine.  But what should we do to
avoid such thing?  AIUI we could document it in
(info "(guix)Application Setup") or (info "(guix)Emacs Initial Setup"),
or even better fix it directly in the code (if possible).

Here is my attempt to fix the code with my naïve elisp programming.  I
would be happy to get better suggestion!