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/77-pointer-assign.c

@@ -0,0 +1,109 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2017 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 <string.h>
+
+#include <mes/lib.h>
+
+struct baz
+{
+  int i;
+  int j;
+};
+
+struct foo
+{
+  int **bar;
+};
+
+void
+add0 (void *ptab)
+{
+  void **pp = *(void ***) ptab;
+bla:
+  pp[0] = 0x11223344;
+}
+
+void
+add1 (void *ptab)
+{
+  void ***x = (void ***) ptab;
+bla:
+  *(void ***) ptab = 0x22334455;
+}
+
+void
+add2 (void *ptab)
+{
+  void ***x = (void ***) ptab;
+bla:
+  *x = 0x33445566;
+}
+
+struct foo *hash_ident[10];
+
+int
+main ()
+{
+  int i = 1;
+  int *p = &i;
+  struct foo f;
+  f.bar = &p;
+  eputs ("f.bar:");
+  eputs (itoa (f.bar));
+  eputs ("\n");
+
+  add0 (&f.bar);
+  eputs ("f.bar:");
+  eputs (itoa (*f.bar));
+  eputs ("\n");
+  if (*f.bar != 0x11223344)
+    return 1;
+
+  add1 (&f.bar);
+  eputs ("f.bar:");
+  eputs (itoa (f.bar));
+  eputs ("\n");
+  if (f.bar != 0x22334455)
+    return 2;
+
+  add2 (&f.bar);
+  eputs ("f.bar:");
+  eputs (itoa (f.bar));
+  eputs ("\n");
+  if (f.bar != 0x33445566)
+    return 3;
+
+  hash_ident[0] = 10;
+  *hash_ident = 0;
+  memset (hash_ident, 0, 10);
+
+  struct baz b;
+  b.i = b.j = 1;
+  if (b.i != 1)
+    return 4;
+
+  struct baz *pb = &b;
+  pb->i = pb->j = 1;
+  if (pb->i != 1)
+    return 5;
+
+  return 0;
+}