GNU ld has prefixed the contents of .gnu.warning.SYMBOL sections

with "warning: " since 2003, so the messages themselves need not
contain the prefix anymore.
From Scott Cheloha
ok jca, deraadt

src/lib/libc/stdlib/rand.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: rand.c,v 1.17 2016/10/22 19:19:34 tb Exp $ */
+/*	$OpenBSD: rand.c,v 1.18 2017/11/28 06:55:49 tb Exp $ */
 /*-
  * Copyright (c) 1990 The Regents of the University of California.
  * All rights reserved.
@@ -44,7 +44,7 @@ DEF_WEAK(rand_r);
 
 #if defined(APIWARN)
 __warn_references(rand_r,
-    "warning: rand_r() is not random, it is deterministic.");
+    "rand_r() is not random, it is deterministic.");
 #endif
 
 int
@@ -57,7 +57,7 @@ rand(void)
 
 #if defined(APIWARN)
 __warn_references(rand,
-    "warning: rand() may return deterministic values, is that what you want?");
+    "rand() may return deterministic values, is that what you want?");
 #endif
 
 void

src/lib/libc/stdlib/random.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: random.c,v 1.30 2016/04/05 04:29:21 guenther Exp $ */
+/*	$OpenBSD: random.c,v 1.31 2017/11/28 06:55:49 tb Exp $ */
 /*
  * Copyright (c) 1983 Regents of the University of California.
  * All rights reserved.
@@ -415,5 +415,5 @@ random(void)
 
 #if defined(APIWARN)
 __warn_references(random,
-    "warning: random() may return deterministic values, is that what you want?");
+    "random() may return deterministic values, is that what you want?");
 #endif

src/lib/libc/string/stpcpy.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: stpcpy.c,v 1.2 2014/07/09 17:08:21 naddy Exp $	*/
+/*	$OpenBSD: stpcpy.c,v 1.3 2017/11/28 06:55:49 tb Exp $	*/
 
 /*
  * Copyright (c) 1988 Regents of the University of California.
@@ -33,7 +33,7 @@
 
 #if defined(APIWARN)
 __warn_references(stpcpy,
-    "warning: stpcpy() is dangerous; do not use it");
+    "stpcpy() is dangerous; do not use it");
 #endif
 
 char *

src/lib/libc/string/strcat.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: strcat.c,v 1.9 2014/06/10 04:17:37 deraadt Exp $	*/
+/*	$OpenBSD: strcat.c,v 1.10 2017/11/28 06:55:49 tb Exp $	*/
 
 /*
  * Copyright (c) 1988 Regents of the University of California.
@@ -33,7 +33,7 @@
 
 #if defined(APIWARN)
 __warn_references(strcat,
-    "warning: strcat() is almost always misused, please use strlcat()");
+    "strcat() is almost always misused, please use strlcat()");
 #endif
 
 char *

src/lib/libc/string/strcpy.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: strcpy.c,v 1.9 2014/06/10 04:17:37 deraadt Exp $	*/
+/*	$OpenBSD: strcpy.c,v 1.10 2017/11/28 06:55:49 tb Exp $	*/
 
 /*
  * Copyright (c) 1988 Regents of the University of California.
@@ -33,7 +33,7 @@
 
 #if defined(APIWARN)
 __warn_references(strcpy,
-    "warning: strcpy() is almost always misused, please use strlcpy()");
+    "strcpy() is almost always misused, please use strlcpy()");
 #endif
 
 char *

src/lib/libc/string/wcscat.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: wcscat.c,v 1.4 2015/09/12 16:23:14 guenther Exp $	*/
+/*	$OpenBSD: wcscat.c,v 1.5 2017/11/28 06:55:49 tb Exp $	*/
 /*	$NetBSD: wcscat.c,v 1.2 2001/01/03 14:29:36 lukem Exp $	*/
 
 /*-
@@ -33,7 +33,7 @@
 
 #if defined(APIWARN)
 __warn_references(wcscat,
-    "warning: wcscat() is almost always misused, please use wcslcat()");
+    "wcscat() is almost always misused, please use wcslcat()");
 #endif
 
 wchar_t *

src/lib/libc/string/wcscpy.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: wcscpy.c,v 1.4 2005/08/08 08:05:37 espie Exp $	*/
+/*	$OpenBSD: wcscpy.c,v 1.5 2017/11/28 06:55:49 tb Exp $	*/
 /*	$NetBSD: wcscpy.c,v 1.2 2001/01/03 14:29:36 lukem Exp $	*/
 
 /*-
@@ -33,7 +33,7 @@
 
 #if defined(APIWARN)
 __warn_references(wcscpy,
-    "warning: wcscpy() is almost always misused, please use wcslcpy()");
+    "wcscpy() is almost always misused, please use wcslcpy()");
 #endif
 
 wchar_t *