Build tzcode with hidden visibility.

Bug: 11156955
Change-Id: Ib98d837b56cbbdfd01687cb3054fe3103eec0da9
diff --git a/libc/include/wchar.h b/libc/include/wchar.h
index d50e9ec..014fed3 100644
--- a/libc/include/wchar.h
+++ b/libc/include/wchar.h
@@ -118,7 +118,7 @@
 extern int               wcscoll(const wchar_t *, const wchar_t *);
 extern wchar_t          *wcscpy(wchar_t *, const wchar_t *);
 extern size_t            wcscspn(const wchar_t *, const wchar_t *);
-extern size_t            wcsftime(wchar_t *, size_t, const wchar_t *, const struct tm *);
+extern size_t            wcsftime(wchar_t *, size_t, const wchar_t *, const struct tm *) __LIBC_ABI_PUBLIC__;
 extern size_t            wcslen(const wchar_t *);
 extern int               wcsncasecmp(const wchar_t *, const wchar_t *, size_t);
 extern wchar_t          *wcsncat(wchar_t *, const wchar_t *, size_t);