Fixed missing const. Include <unistd.h> so that the function type gets

checked.
Submitted by:	partly by roberto

lib/libc/sys/truncate.c

@@ -38,13 +38,15 @@ static char sccsid[] = "@(#)truncate.c	8.1 (Berkeley) 6/17/93";
 #include <sys/types.h>
 #include <sys/syscall.h>
 
+#include <unistd.h>
+
 /*
  * This function provides 64-bit offset padding that
  * is not supplied by GCC 1.X but is supplied by GCC 2.X.
  */
 int
 truncate(path, length)
-	char 	*path;
+	const char	*path;
 	off_t	length;
 {