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/tests/scaffold/65-read.c

@@ -0,0 +1,87 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2017,2019 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 <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct scm
+{
+  int type;
+  int car;
+  int cdr;
+};
+
+char g_arena[84];
+#if __MESC__
+struct scm *g_cells = g_arena;
+#else
+struct scm *g_cells = (struct scm *) g_arena;
+#endif
+char *g_chars = g_arena;
+
+int g = 48;
+int
+get ()
+{
+  int i = g;
+  g++;
+  return i;
+}
+
+int
+main ()
+{
+  char *p = (char *) g_chars;
+  int i = 0;
+
+  oputs ("\n: ");
+  oputs ("t: read 0123456789\nt: ");
+  int c = get ();
+  while (i < 10)
+    {
+      *p++ = c;
+      putchar (c);
+      c = get ();
+      i++;
+    }
+  oputs ("\n");
+  if (strcmp (g_chars, "0123456789"))
+    return 1;
+
+  oputs ("t: fdungetc ('A') == getchar ()\n");
+  fdungetc ('A', STDIN);
+  if (getchar () != 'A')
+    return 2;
+  oputs ("t: fdungetc (0)\n");
+  fdungetc (0, STDIN);
+  if (getchar () != 0)
+    return 3;
+
+  oputs ("t: i == 'm'\n");
+  char m = 0x1122336d;
+  i = m;
+  if (i != 'm')
+    return 4;
+
+  return 0;
+}