Use const instead of __const, and merge the license change from NetBSD.

Obtained from:	NetBSD

lib/libc/gen/fmtcheck.c

@@ -1,3 +1,5 @@
+/*	$NetBSD: fmtcheck.c,v 1.8 2008/04/28 20:22:59 martin Exp $	*/
+
 /*-
  * Copyright (c) 2000 The NetBSD Foundation, Inc.
  * All rights reserved.
@@ -12,13 +14,6 @@
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *        This product includes software developed by the NetBSD
- *        Foundation, Inc. and its contributors.
- * 4. Neither the name of The NetBSD Foundation nor the names of its
- *    contributors may be used to endorse or promote products derived
- *    from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
@@ -33,7 +28,6 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
-/*	$NetBSD: fmtcheck.c,v 1.2 2000/11/01 01:17:20 briggs Exp $	*/
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
@@ -308,7 +302,7 @@ get_next_format(const char **pf, EFT eft)
 	/*NOTREACHED*/
 }
 
-__const char *
+const char *
 __fmtcheck(const char *f1, const char *f2)
 {
 	const char	*f1p, *f2p;