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/stdio/fread.c

@@ -0,0 +1,76 @@
+/* -*-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>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+int
+__fungetc_p (FILE * stream)
+{
+  return __ungetc_p ((int) (long) stream);
+}
+
+size_t
+fread (void *data, size_t size, size_t count, FILE * stream)
+{
+  if (!size || !count)
+    return 0;
+
+  size_t todo = size * count;
+  char *buf = (char *) data;
+
+  int bytes = 0;
+  while (__fungetc_p (stream) && todo-- && ++bytes)
+    *buf++ = fgetc (stream);
+  int filedes = (long) stream;
+  if (todo)
+    {
+      int r = read (filedes, buf, todo);
+      if (r < 0 && !bytes)
+        bytes = r;
+      else
+        bytes += r;
+    }
+
+  if (__mes_debug ())
+    {
+      static char debug_buf[4096];
+      eputs ("fread fd=");
+      eputs (itoa (filedes));
+      eputs (" bytes=");
+      eputs (itoa (bytes));
+      eputs ("\n");
+      if (bytes > 0 && bytes < sizeof (debug_buf))
+        {
+          strncpy (debug_buf, data, bytes);
+          buf[bytes] = 0;
+          eputs ("fread buf=");
+          eputs (debug_buf);
+          eputs ("\n");
+        }
+    }
+
+  if (bytes > 0)
+    return bytes / size;
+
+  return 0;
+}