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/mes/fdgetc.c

@@ -0,0 +1,74 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2016,2017,2018,2019 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 <limits.h>
+#include <string.h>
+#include <sys/resource.h>
+#include <unistd.h>
+
+int __ungetc_buf[__FILEDES_MAX + 1] = { 0 };
+
+int
+__ungetc_p (int filedes)
+{
+  return __ungetc_buf[filedes] >= 0;
+}
+
+void
+__ungetc_init ()
+{
+  if (__ungetc_buf[__FILEDES_MAX] == 0)
+    memset (__ungetc_buf, -1, (__FILEDES_MAX + 1) * sizeof (int));
+}
+
+void
+__ungetc_clear (int filedes)
+{
+  __ungetc_buf[filedes] = -1;
+}
+
+void
+__ungetc_set (int filedes, int c)
+{
+  __ungetc_buf[filedes] = c;
+}
+
+int
+fdgetc (int fd)
+{
+  __ungetc_init ();
+
+  char c;
+  int i = __ungetc_buf[fd];
+  if (i >= 0)
+    __ungetc_buf[fd] = -1;
+  else
+    {
+      int r = read (fd, &c, 1);
+      if (r < 1)
+        return -1;
+      i = (int) c;
+    }
+  if (i < 0)
+    i += 256;
+
+  return i;
+}