Add mes and mescc-tools-extra

mescc-tools-extra contains two important tools:
- cp
- chmod

mes first builds itself from a mes 0.21 seed as used by guix, and then
builds a mes 0.22 and then mes 0.22 using that created mes 0.22.

It does /not/ use bootstrap.sh as we don't have a proper shell at this
point, it has been manually adapted for kaem.

sysa/mes-0.22/guix.scm

@@ -0,0 +1,43 @@
+;;; guix.scm -- Guix package definition
+
+;;; GNU Mes --- Maxwell Equations of Software
+;;; Copyright © 2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+;;;
+;;; This file is part of GNU Mes.
+;;;
+;;; GNU Mes is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Mes is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; GNU Guix development package.  To build and install, run:
+;;
+;;   guix package -f guix.scm
+;;
+;; To build it, but not install it, run:
+;;
+;;   guix build -f guix.scm
+;;
+;; To use as the basis for a development environment, run:
+;;
+;;   guix environment -l guix.scm
+;;
+;;; Code:
+
+(define %source-dir (dirname (current-filename)))
+(add-to-load-path (string-append %source-dir "/guix"))
+
+(use-modules (git mes))
+
+;; Return it here so `guix build/environment/package' can consume it directly.
+mes.git