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/scripts/diff.scm

@@ -0,0 +1,140 @@
+#! /bin/sh
+# -*-scheme-*-
+mes_p=$(command -v mes)
+if [ "$mes_p" -a -z "$MES" ]; then
+    MES=guile
+fi
+exec ${MES-mes} -L ${0%/*} -e '(diff)' -s "$0" "$@"
+!#
+
+;;; GNU Mes --- Maxwell Equations of Software
+;;; Copyright © 2016,2017,2018 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+;;;
+;;; mes-snarf.scm: 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/>.
+
+(define-module (diff)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-9)
+  #:use-module (ice-9 rdelim)
+  #:export (main))
+
+(cond-expand
+ (mes
+  (define %scheme "mes"))
+ (guile-2
+  (define %scheme "guile")
+  (define-macro (mes-use-module . rest) #t))
+ (guile
+  (use-modules (ice-9 syncase))
+  (define %scheme "guile")
+  (define-macro (mes-use-module . rest) #t)))
+
+(mes-use-module (mes guile))
+
+(format (current-error-port) "diff[~a]...\n" %scheme)
+
+(define (plus a)
+  (string-append "+" a))
+(define (minus a)
+  (string-append "-" a))
+(define (keep a)
+  (string-append " " a))
+
+(define-record-type <hunk> (make-hunk context after removed added)
+  hunk?
+  (context hunk.context)
+  (after hunk.after)
+  (removed hunk.removed)
+  (added hunk.added))
+
+(define (hunk->lines o)
+  (append `(,(format #f "@@ -~a,~a +~a,~a" (length (hunk.removed o)) (+ 3 (car (hunk.context o))) (length (hunk.added o)) (+ 3 (cadr (hunk.context o))))
+            ,@(map keep (filter identity (cddr (hunk.context o)))))
+          (map minus (hunk.removed o))
+          (map plus (hunk.added o))
+          (map keep (hunk.after o))))
+
+(define (safe-list-head lst n)
+  (list-head lst (min n (length lst))))
+
+(define (line-equal? a b)
+  (equal? (string-trim-right a) (string-trim-right b)))
+
+(define (diff-files a b)
+  (let ((a-lines (string-split (with-input-from-file a read-string) #\newline))
+        (b-lines (string-split (with-input-from-file b read-string) #\newline)))
+    (let loop ((context '(1 1 #f #f #f)) (a-lines a-lines) (b-lines b-lines))
+      ;;(format (current-error-port) "loop context=~s\n" context)
+      (cond ((and (null? a-lines) (null? b-lines)) '())
+            ((null? a-lines)
+             (list (make-hunk context (safe-list-head a-lines 3) '() b-lines)))
+            ((null? b-lines)
+             (list (make-hunk context (safe-list-head a-lines 3) a-lines '())))
+            ((line-equal? (car a-lines) (car b-lines))
+             (loop `(,(1+ (car context))
+                     ,(1+ (cadr context))
+                     ,@(cdddr context)
+                     ,(car a-lines))
+                   (cdr a-lines) (cdr b-lines)))
+            (else
+             (cond ((and (pair? (cdr b-lines)) (line-equal? (car a-lines) (cadr b-lines)))
+                    (cons (make-hunk context (safe-list-head a-lines 3) '() (list (car b-lines)))
+                          (loop `(,(+ 1 (car context))
+                                  ,(+ 2 (cadr context))
+                                  ,@(cdddr context)
+                                  ,(car a-lines))
+                                (cdr a-lines) (cddr b-lines))))
+                   ((and (pair? (cdr a-lines)) (line-equal? (cadr a-lines) (car b-lines)))
+                    (cons (make-hunk context (safe-list-head a-lines 3) (list (car a-lines)) '())
+                          (loop `(,(+ 2 (car context))
+                                  ,(+ 1 (cadr context))
+                                  ,@(cddddr context)
+                                  ,(car a-lines)
+                                  ,(cadr a-lines))
+                                (cddr a-lines) (cdr b-lines))))
+                   (else (cons (make-hunk context (safe-list-head a-lines 3) (list (car a-lines)) (list (car b-lines)))
+                               (loop `(,(1+ (car context))
+                                       ,(1+ (cadr context))
+                                       ,@(cdddr context)
+                                       ,(car a-lines))
+                                     (cdr a-lines) (cdr b-lines))))))))))
+
+(define (main args)
+  (let ((files (cdr args)))
+    (when (or (null? files)
+              (equal? (car files) "-h")
+              (equal? (car files) "--help"))
+      (display "
+Usage: diff.scm [OPTION]... FILES
+Compare FILES line by line.
+
+Options:
+  -u,--unified        display unified diff (default)
+  -h,--help           display this help and exit
+  -V,--version        display version information and exit
+")
+      (exit (if (null? files) 2 0)))
+    (when (or (equal? (car files) "-V")
+              (equal? (car files) "--version"))
+      (display "
+diff.scm (GNU Mes) 0.20
+"))
+    (let* ((files (if (string-prefix? "-" (car files)) (cdr files) files))
+           (hunks (apply diff-files (list-head files 2))))
+     (when (pair? hunks)
+       (display (string-join (append-map hunk->lines hunks) "\n"))
+       (newline)
+       (exit 1)))))