first usable version of kernel and commands

After an year of hard work, this is a first "usable" version of Jehanne.

sys/include/apw/libc.wrapper.h

@@ -0,0 +1,37 @@
+/*
+ * This file is part of Jehanne.
+ *
+ * Copyright (C) 2016 Giacomo Tesio <giacomo@tesio.it>
+ *
+ * Jehanne 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, version 2 of the License.
+ *
+ * Jehanne 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 Jehanne.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* This wrapper protect Jehanne default headers from multiple
+ * inclusions in POSIX source code.
+ *
+ * As far as u.h and libc.h are not standard headers in POSIX, a simple
+ * guarded inclusion will go to the appropriate folders /arch/amd64/include
+ * and /sys/include
+ */
+#ifndef _JEHANNE_LIBC_WRAPPER
+#define _JEHANNE_LIBC_WRAPPER
+#ifdef __cplusplus
+extern "C" {
+#endif
+#include <u.h>
+#include "../libc.h"
+#undef JEHANNE_LIBC
+#ifdef __cplusplus
+}
+#endif
+#endif