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/lib/string/strerror.c

@@ -0,0 +1,81 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * 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/>.
+ */
+
+#include <mes/lib.h>
+#include <string.h>
+
+char *sys_errlist[] = {
+  "error 00",
+  "error 01",
+  "error 02",
+  "error 03",
+  "error 04",
+  "error 05",
+  "error 06",
+  "error 07",
+  "error 08",
+  "error 09",
+  "error 10",
+  "error 11",
+  "error 12",
+  "error 13",
+  "error 14",
+  "error 15",
+  "error 16",
+  "error 17",
+  "error 18",
+  "error 19",
+  "error 20",
+  "error 21",
+  "error 22",
+  "error 23",
+  "error 24",
+  "error 25",
+  "error 26",
+  "error 27",
+  "error 28",
+  "error 29",
+  "error 30",
+  "error 31",
+  "error 32",
+  "error 33",
+  "error 34",
+  "error 35",
+  "error 36",
+  "error 37",
+  "error 38",
+  "error 39",
+};
+
+int sys_nerr = 39;
+
+char *
+strerror (int errnum)
+{
+  if (__mes_debug ())
+    {
+      eputs ("strerror errnum=");
+      eputs (itoa (errnum));
+      eputs ("\n");
+    }
+  if (errnum > 0 && errnum <= sys_nerr)
+    return sys_errlist[errnum];
+  return "sterror: unknown error";
+}