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/include/dirent.h

@@ -0,0 +1,76 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright (C) 1991, 1992 Free Software Foundation, Inc.
+ * Copyright © 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/>.
+ */
+
+#ifndef __MES_DIRENT_H
+#define __MES_DIRENT_H 1
+
+#if SYSTEM_LIBC
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#undef __MES_DIRENT_H
+#include_next <dirent.h>
+
+#else // ! SYSTEM_LIBC
+
+#include <dirstream.h>
+
+// Taken from GNU C Library 1.06.4, 2.2.5
+
+/*
+ *	POSIX Standard: 5.1.2 Directory Operations	<dirent.h>
+ */
+
+#include <stddef.h>
+
+int __getdirentries (int filedes, char *buffer, size_t nbytes, off_t * basep);
+
+struct dirent
+{
+  ino_t d_ino;
+  off_t d_off;
+  unsigned short int d_reclen;
+#if 0
+  unsigned char d_type;
+#endif
+  char d_name[256];             /* We must not include limits.h! */
+};
+
+/* Open a directory stream on NAME.
+   Return a DIR stream on the directory, or NULL if it could not be opened.  */
+DIR *opendir (char const *name);
+
+/* Close the directory stream DIRP.
+   Return 0 if successful, -1 if not.  */
+int closedir (DIR * dirp);
+
+/* Read a directory entry from DIRP.
+   Return a pointer to a `struct dirent' describing the entry,
+   or NULL for EOF or error.  The storage returned may be overwritten
+   by a later readdir call on the same DIR stream.  */
+struct dirent *readdir (DIR * dirp);
+
+/* Rewind DIRP to the beginning of the directory.  */
+extern void rewinddir (DIR * dirp);
+
+#endif // ! SYSTEM_LIBC
+
+#endif // __MES_DIRENT_H