diff --git a/newlib/libc/include/string.h b/newlib/libc/include/string.h
index 8f4fd2e20..ba5e51ee7 100644
--- a/newlib/libc/include/string.h
+++ b/newlib/libc/include/string.h
@@ -48,13 +48,14 @@ char 	*_EXFUN(strtok,(char *__restrict, const char *__restrict));
 size_t	 _EXFUN(strxfrm,(char *__restrict, const char *__restrict, size_t));
 
 #if __POSIX_VISIBLE >= 200809
-extern int strcasecmp_l (const char *, const char *, locale_t);
-extern int strncasecmp_l (const char *, const char *, size_t, locale_t);
-extern int strcoll_l (const char *, const char *, locale_t);
-extern size_t strxfrm_l (char *__restrict, const char *__restrict, size_t,
-			 locale_t);
+int	 strcoll_l (const char *, const char *, locale_t);
+char	*strerror_l (int, locale_t);
+size_t	 strxfrm_l (char *__restrict, const char *__restrict, size_t, locale_t);
+#endif
+#if __GNU_VISIBLE
+int	 strcasecmp_l (const char *, const char *, locale_t);
+int	 strncasecmp_l (const char *, const char *, size_t, locale_t);
 #endif
-
 #if __MISC_VISIBLE || __POSIX_VISIBLE
 char 	*_EXFUN(strtok_r,(char *__restrict, const char *__restrict, char **__restrict));
 #endif
diff --git a/newlib/libc/include/strings.h b/newlib/libc/include/strings.h
index b462d07f8..be019581c 100644
--- a/newlib/libc/include/strings.h
+++ b/newlib/libc/include/strings.h
@@ -15,6 +15,10 @@
 #include <sys/cdefs.h>
 #include <sys/types.h> /* for size_t */
 
+#if __POSIX_VISIBLE >= 200809
+#include <sys/_locale.h>
+#endif
+
 _BEGIN_STD_C
 
 #if __BSD_VISIBLE || (__POSIX_VISIBLE && __POSIX_VISIBLE < 200809)
@@ -33,10 +37,10 @@ int	 _EXFUN(ffs,(int));
 int	 _EXFUN(strcasecmp,(const char *, const char *));
 int	 _EXFUN(strncasecmp,(const char *, const char *, size_t));
 
-#if __GNU_VISIBLE
-extern int strcasecmp_l (const char *, const char *, locale_t);
-extern int strncasecmp_l (const char *, const char *, size_t, locale_t);
-#endif /* _GNU_VISIBLE */
+#if __POSIX_VISIBLE >= 200809
+int	 strcasecmp_l (const char *, const char *, locale_t);
+int	 strncasecmp_l (const char *, const char *, size_t, locale_t);
+#endif /* __POSIX_VISIBLE >= 200809 */
 
 _END_STD_C