first usable version of kernel and commands

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

sys/include/apw/stdio.h

@@ -0,0 +1,43 @@
+/*
+ * 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/>.
+ */
+#ifndef _STDIO_H
+#define _STDIO_H
+
+/* Simple trick to avoid name clash between native and standard headers:
+ *
+ * when you use stdio.h in native Jehanne code, you have to include it
+ * after u.h and libc.h: thus in native code, JEHANNE_LIBC will already
+ * be defined, while in posix code it will not (and it will undef at
+ * the first includsion of the wrapper)
+ *
+ * This way, defining JEHANNE_LIBC is all we have to do in libc.h to
+ * cope with ANSI/POSIX pollution, without introducing ifdef guards.
+ */
+#ifndef JEHANNE_LIBC
+#include "libc.wrapper.h"
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+#include "../stdio.h"
+#ifdef __cplusplus
+}
+#endif
+#endif
+