Gave vsprintf.c its own header file, and made console.h include it.

src/include/vsprintf.h

@@ -0,0 +1,14 @@
+#ifndef VSPRINTF_H
+#define VSPRINTF_H
+
+/*
+ * Note that we cannot use __attribute__ (( format ( printf, ... ) ))
+ * to get automatic type checking on arguments, because we use
+ * non-standard format characters such as "%!" and "%@".
+ *
+ */
+
+extern int sprintf ( char *buf, const char *fmt, ... );
+extern void printf ( const char *fmt, ... );
+
+#endif /* VSPRINTF_H */