first usable version of kernel and commands

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

sys/include/apw/stdlib.h

@@ -0,0 +1,55 @@
+/*
+ * 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 _STDLIB_H
+#define _STDLIB_H
+#include "libc.wrapper.h"
+
+#define EXIT_SUCCESS 0
+#define EXIT_FAILURE 1	// POSIX
+
+#define __POSIX_EXIT_PREFIX "posix exit: "
+
+typedef	struct {
+	int	quot;
+	int	rem;
+} div_t;
+
+typedef struct {
+	long	quot;
+	long	rem;
+} ldiv_t;
+
+extern void exit(int status);
+
+extern int system(const char *command);
+
+extern div_t div(int num, int denom);
+
+extern ldiv_t ldiv(long num, long denom);
+
+extern void* bsearch(const void* key, const void* base, size_t nmemb, size_t size,
+		int (*compar)(const void*, const void*));
+
+#undef abort
+extern void abort(void);
+
+#undef L_eprintf
+extern void __eprintf(const char *format, const char *file,
+		unsigned int line, const char *expression);
+
+#endif