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/7b-struct-int-array.c

@@ -0,0 +1,103 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2017,2018 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>
+
+struct foo
+{
+  int a;
+  int b;
+};
+
+struct foo g_foo[2] = { 0, 1, 2, 3 };
+
+struct bar
+{
+  int bar[4];
+};
+
+struct bar g_bar = { 101, 102 };
+
+typedef struct bar bar_struct;
+typedef struct bar foo_struct;
+
+int
+main ()
+{
+  if (g_foo[0].a != 0)
+    return 1;
+  if (g_foo[0].b != 1)
+    return 2;
+  if (g_foo[1].a != 2)
+    return 3;
+  if (g_foo[1].b != 3)
+    return 4;
+
+  void *p = &g_foo;
+  struct foo *pfoo = (((struct foo *) p) + 1);
+  if (pfoo->a != 2)
+    return 5;
+  if (pfoo->b != 3)
+    return 6;
+
+  int *pi = &g_foo;
+  if (*pi != 0)
+    return 7;
+
+  pi = &g_bar;
+  if (*pi != 101)
+    return 8;
+
+  struct bar bar = { 0x22, 0x33 };
+  pi = &bar;
+  if (*pi != 0x22)
+    return 9;
+
+  bar_struct bs;
+  bs.bar[0] = 102;
+  pi = &bs;
+  if (*pi != 102)
+    return 10;
+
+  foo_struct fs;
+  fs.bar[0] = 0x22;
+  fs.bar[1] = 0x33;
+
+  pi = &fs;
+  if (*pi != 0x22)
+    return 11;
+  pi++;
+
+  if (*pi != 0x33)
+    return 12;
+
+  foo_struct *pfs = &fs;
+  pfs->bar[3] = 0x44;
+  pfs->bar[4] = 0x55;
+
+  pi = &fs.bar[3];
+  if (*pi != 0x44)
+    return 13;
+  pi++;
+  if (*pi != 0x55)
+    return 14;
+
+  return 0;
+}