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/7h-struct-assign.c

@@ -0,0 +1,179 @@
+/* -*-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 <mes/lib.h>
+#include <string.h>
+
+struct string
+{
+  char *str;
+  int len;
+};
+
+typedef struct biggie
+{
+  int a;
+  int b;
+  int c;
+  char *str;
+  int len;
+} biggie;
+
+struct other
+{
+  struct biggie big;
+};
+
+struct string g_t;
+
+struct biggie tab[2];
+
+int
+main ()
+{
+  struct string s = { "hallo" };
+  s.len = strlen (s.str);
+  eputs (s.str);
+  eputs ("\n");
+
+  struct string t;
+  t = s;
+
+  eputs (t.str);
+  eputs ("\n");
+  if (t.len != s.len)
+    return 1;
+  if (strcmp (t.str, s.str))
+    return 2;
+
+  g_t = s;
+  eputs (g_t.str);
+  eputs ("\n");
+  if (g_t.len != s.len)
+    return 3;
+  if (strcmp (g_t.str, s.str))
+    return 4;
+
+  struct biggie b;
+  b.str = "hello";
+  b.len = strlen (b.str);
+  eputs (b.str);
+  eputs ("\n");
+
+  struct biggie tb;
+  tb = b;
+  eputs (tb.str);
+  eputs ("\n");
+  if (tb.len != b.len)
+    return 5;
+  if (strcmp (tb.str, b.str))
+    return 6;
+
+  b.str = "bye";
+  b.len = strlen (b.str);
+  eputs (b.str);
+  eputs ("\n");
+  //struct biggie *pb = &tb;
+  biggie *pb = &tb;
+  *pb = b;
+  eputs (tb.str);
+  eputs ("\n");
+  if (tb.len != b.len)
+    return 7;
+  if (strcmp (tb.str, b.str))
+    return 8;
+
+  tb.str = "there";
+  tb.len = strlen (tb.str);
+
+  b = *pb;
+  eputs (b.str);
+  eputs ("\n");
+  if (b.len != tb.len)
+    return 9;
+  if (strcmp (b.str, tb.str))
+    return 10;
+
+  char **x = &b.str;
+  char *p;
+  p = *x;
+
+  struct other o;
+  struct other *po = &o;
+  po->big = b;
+  eputs (o.big.str);
+  eputs ("\n");
+  if (o.big.len != b.len)
+    return 13;
+  if (strcmp (o.big.str, b.str))
+    return 14;
+
+  po->big = *pb;
+  eputs (o.big.str);
+  eputs ("\n");
+  if (o.big.len != b.len)
+    return 15;
+  if (strcmp (o.big.str, b.str))
+    return 16;
+
+  b.str = "* = *";
+  b.len = strlen (b.str);
+  eputs (b.str);
+  eputs ("\n");
+  struct biggie *q = tab;
+  pb = &b;
+  *q++ = *pb;
+  eputs (tab[0].str);
+  eputs ("\n");
+  if (tab[0].len != b.len)
+    return 17;
+  if (strcmp (tab[0].str, b.str))
+    return 18;
+
+  tab[1] = tab[0];
+  eputs (tab[1].str);
+  eputs ("\n");
+  if (tab[1].len != b.len)
+    return 19;
+  if (strcmp (tab[1].str, b.str))
+    return 20;
+
+  tab[0].str = "burp";
+  tab[0].len = strlen (tab[1].str);
+  eputs (tab[0].str);
+  eputs ("\n");
+  b = tab[0];
+  eputs (b.str);
+  eputs ("\n");
+  if (b.len != tab[0].len)
+    return 21;
+  if (strcmp (b.str, tab[0].str))
+    return 22;
+
+  tab[1] = b;
+  eputs (tab[1].str);
+  eputs ("\n");
+  if (tab[1].len != b.len)
+    return 23;
+  if (strcmp (tab[1].str, b.str))
+    return 24;
+
+  return 0;
+}