More OpenBSD cleanup (primarily string).

This patch removes the string/ and wchar/ directories.

Change-Id: Ia489904bc67047e4bc79acb1f3eec21aa3fe5f0d
diff --git a/libc/include/string.h b/libc/include/string.h
index 37d22c4..8963e3d 100644
--- a/libc/include/string.h
+++ b/libc/include/string.h
@@ -49,6 +49,7 @@
 extern char* __strchr_chk(const char *, int, size_t);
 
 extern char*  strrchr(const char *, int) __purefunc;
+extern char* __strrchr_chk(const char *, int, size_t);
 
 extern size_t strlen(const char *) __purefunc;
 extern size_t __strlen_chk(const char *, size_t);
@@ -263,8 +264,6 @@
     return __strchr_chk(s, c, bos);
 }
 
-extern char* __strrchr_chk(const char *, int, size_t);
-
 __BIONIC_FORTIFY_INLINE
 char* strrchr(const char *s, int c) {
     size_t bos = __bos(s);