diff --git a/libc/Android.bp b/libc/Android.bp
index 4cf31bc..51a7bf0 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -343,10 +343,6 @@
         "upstream-netbsd/lib/libc/stdlib/reallocarr.c",
         "upstream-netbsd/lib/libc/stdlib/seed48.c",
         "upstream-netbsd/lib/libc/stdlib/srand48.c",
-        "upstream-netbsd/lib/libc/string/memccpy.c",
-        "upstream-netbsd/lib/libc/string/strcasestr.c",
-        "upstream-netbsd/lib/libc/string/strcoll.c",
-        "upstream-netbsd/lib/libc/string/strxfrm.c",
     ],
     multilib: {
         lib32: {
@@ -468,7 +464,10 @@
         "upstream-openbsd/lib/libc/stdlib/setenv.c",
         "upstream-openbsd/lib/libc/stdlib/tfind.c",
         "upstream-openbsd/lib/libc/stdlib/tsearch.c",
+        "upstream-openbsd/lib/libc/string/memccpy.c",
         "upstream-openbsd/lib/libc/string/strcasecmp.c",
+        "upstream-openbsd/lib/libc/string/strcasestr.c",
+        "upstream-openbsd/lib/libc/string/strcoll.c",
         "upstream-openbsd/lib/libc/string/strcspn.c",
         "upstream-openbsd/lib/libc/string/strdup.c",
         "upstream-openbsd/lib/libc/string/strndup.c",
@@ -477,6 +476,7 @@
         "upstream-openbsd/lib/libc/string/strspn.c",
         "upstream-openbsd/lib/libc/string/strstr.c",
         "upstream-openbsd/lib/libc/string/strtok.c",
+        "upstream-openbsd/lib/libc/string/strxfrm.c",
         "upstream-openbsd/lib/libc/string/wcslcpy.c",
         "upstream-openbsd/lib/libc/string/wcswidth.c",
     ],
diff --git a/libc/upstream-netbsd/lib/libc/string/memccpy.c b/libc/upstream-openbsd/lib/libc/string/memccpy.c
similarity index 83%
rename from libc/upstream-netbsd/lib/libc/string/memccpy.c
rename to libc/upstream-openbsd/lib/libc/string/memccpy.c
index c086241..635061b 100644
--- a/libc/upstream-netbsd/lib/libc/string/memccpy.c
+++ b/libc/upstream-openbsd/lib/libc/string/memccpy.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: memccpy.c,v 1.13 2012/06/25 22:32:46 abs Exp $	*/
+/*	$OpenBSD: memccpy.c,v 1.7 2015/08/31 02:53:57 guenther Exp $	*/
 
 /*-
  * Copyright (c) 1990, 1993
@@ -29,25 +29,12 @@
  * SUCH DAMAGE.
  */
 
-#include <sys/cdefs.h>
-#if defined(LIBC_SCCS) && !defined(lint)
-#if 0
-static char sccsid[] = "@(#)memccpy.c	8.1 (Berkeley) 6/4/93";
-#else
-__RCSID("$NetBSD: memccpy.c,v 1.13 2012/06/25 22:32:46 abs Exp $");
-#endif
-#endif /* LIBC_SCCS and not lint */
-
-#include <assert.h>
 #include <string.h>
 
 void *
 memccpy(void *t, const void *f, int c, size_t n)
 {
 
-	_DIAGASSERT(t != 0);
-	_DIAGASSERT(f != 0);
-
 	if (n) {
 		unsigned char *tp = t;
 		const unsigned char *fp = f;
@@ -59,3 +46,4 @@
 	}
 	return (0);
 }
+DEF_WEAK(memccpy);
diff --git a/libc/upstream-netbsd/lib/libc/string/strcasestr.c b/libc/upstream-openbsd/lib/libc/string/strcasestr.c
similarity index 83%
rename from libc/upstream-netbsd/lib/libc/string/strcasestr.c
rename to libc/upstream-openbsd/lib/libc/string/strcasestr.c
index f8a9444..abb3e15 100644
--- a/libc/upstream-netbsd/lib/libc/string/strcasestr.c
+++ b/libc/upstream-openbsd/lib/libc/string/strcasestr.c
@@ -1,4 +1,5 @@
-/*	$NetBSD: strcasestr.c,v 1.3 2005/11/29 03:12:00 christos Exp $	*/
+/*	$OpenBSD: strcasestr.c,v 1.4 2015/08/31 02:53:57 guenther Exp $	*/
+/*	$NetBSD: strcasestr.c,v 1.2 2005/02/09 21:35:47 kleink Exp $	*/
 
 /*-
  * Copyright (c) 1990, 1993
@@ -32,13 +33,6 @@
  * SUCH DAMAGE.
  */
 
-#include <sys/cdefs.h>
-#if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: strcasestr.c,v 1.3 2005/11/29 03:12:00 christos Exp $");
-#endif /* LIBC_SCCS and not lint */
-
-#include "namespace.h"
-#include <assert.h>
 #include <ctype.h>
 #include <string.h>
 
@@ -51,11 +45,8 @@
 	char c, sc;
 	size_t len;
 
-	_DIAGASSERT(s != NULL);
-	_DIAGASSERT(find != NULL);
-
 	if ((c = *find++) != 0) {
-		c = tolower((unsigned char)c);
+		c = (char)tolower((unsigned char)c);
 		len = strlen(find);
 		do {
 			do {
@@ -65,5 +56,6 @@
 		} while (strncasecmp(s, find, len) != 0);
 		s--;
 	}
-	return __UNCONST(s);
+	return ((char *)s);
 }
+DEF_WEAK(strcasestr);
diff --git a/libc/upstream-netbsd/lib/libc/string/strcoll.c b/libc/upstream-openbsd/lib/libc/string/strcoll.c
similarity index 78%
rename from libc/upstream-netbsd/lib/libc/string/strcoll.c
rename to libc/upstream-openbsd/lib/libc/string/strcoll.c
index 77a0942..47a6ea4 100644
--- a/libc/upstream-netbsd/lib/libc/string/strcoll.c
+++ b/libc/upstream-openbsd/lib/libc/string/strcoll.c
@@ -1,8 +1,7 @@
-/*	$NetBSD: strcoll.c,v 1.10 2012/06/25 22:32:46 abs Exp $	*/
-
+/*	$OpenBSD: strcoll.c,v 1.6 2015/08/31 02:53:57 guenther Exp $ */
 /*-
- * Copyright (c) 1990, 1993
- *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 1990 The Regents of the University of California.
+ * All rights reserved.
  *
  * This code is derived from software contributed to Berkeley by
  * Chris Torek.
@@ -32,16 +31,6 @@
  * SUCH DAMAGE.
  */
 
-#include <sys/cdefs.h>
-#if defined(LIBC_SCCS) && !defined(lint)
-#if 0
-static char sccsid[] = "@(#)strcoll.c	8.1 (Berkeley) 6/4/93";
-#else
-__RCSID("$NetBSD: strcoll.c,v 1.10 2012/06/25 22:32:46 abs Exp $");
-#endif
-#endif /* LIBC_SCCS and not lint */
-
-#include <assert.h>
 #include <string.h>
 
 /*
@@ -50,10 +39,7 @@
 int
 strcoll(const char *s1, const char *s2)
 {
-
-	_DIAGASSERT(s1 != NULL);
-	_DIAGASSERT(s2 != NULL);
-
 	/* LC_COLLATE is unimplemented, hence always "C" */
 	return (strcmp(s1, s2));
 }
+DEF_STRONG(strcoll);
diff --git a/libc/upstream-netbsd/lib/libc/string/strxfrm.c b/libc/upstream-openbsd/lib/libc/string/strxfrm.c
similarity index 73%
rename from libc/upstream-netbsd/lib/libc/string/strxfrm.c
rename to libc/upstream-openbsd/lib/libc/string/strxfrm.c
index 42c2a24..97df097 100644
--- a/libc/upstream-netbsd/lib/libc/string/strxfrm.c
+++ b/libc/upstream-openbsd/lib/libc/string/strxfrm.c
@@ -1,8 +1,7 @@
-/*	$NetBSD: strxfrm.c,v 1.12 2012/06/25 22:32:46 abs Exp $	*/
-
+/*	$OpenBSD: strxfrm.c,v 1.7 2015/08/31 02:53:57 guenther Exp $ */
 /*-
- * Copyright (c) 1990, 1993
- *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 1990 The Regents of the University of California.
+ * All rights reserved.
  *
  * This code is derived from software contributed to Berkeley by
  * Chris Torek.
@@ -32,16 +31,6 @@
  * SUCH DAMAGE.
  */
 
-#include <sys/cdefs.h>
-#if defined(LIBC_SCCS) && !defined(lint)
-#if 0
-static char sccsid[] = "@(#)strxfrm.c	8.1 (Berkeley) 6/4/93";
-#else
-__RCSID("$NetBSD: strxfrm.c,v 1.12 2012/06/25 22:32:46 abs Exp $");
-#endif
-#endif /* LIBC_SCCS and not lint */
-
-#include <assert.h>
 #include <string.h>
 
 /*
@@ -52,19 +41,12 @@
 size_t
 strxfrm(char *dst, const char *src, size_t n)
 {
-	size_t srclen, copysize;
-
-	_DIAGASSERT(src != NULL);
 
 	/*
 	 * Since locales are unimplemented, this is just a copy.
 	 */
-	srclen = strlen(src);
-	if (n != 0) {
-		_DIAGASSERT(dst != NULL);
-		copysize = srclen < n ? srclen : n - 1;
-		(void)memcpy(dst, src, copysize);
-		dst[copysize] = 0;
-	}
-	return (srclen);
+	if (n == 0)
+		return (strlen(src));
+	return (strlcpy(dst, src, n));
 }
+DEF_STRONG(strxfrm);