first usable version of kernel and commands

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

sys/src/lib/stdio/vsprintf.c

@@ -0,0 +1,23 @@
+/*
+ * This file is part of the UCB release of Plan 9. It is subject to the license
+ * terms in the LICENSE file found in the top-level directory of this
+ * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
+ * part of the UCB release of Plan 9, including this file, may be copied,
+ * modified, propagated, or distributed except according to the terms contained
+ * in the LICENSE file.
+ */
+
+/*
+ * pANS stdio -- vsprintf
+ */
+#include "iolib.h"
+int vsprintf(char *buf, const char *fmt, va_list args){
+	int n;
+	FILE *f=sopenw();
+	if(f==NULL)
+		return 0;
+	setvbuf(f, buf, _IOFBF, 100000);
+	n=vfprintf(f, fmt, args);
+	sclose(f);
+	return n;
+}