[libc++] Explicitly mark basic_string<...>::npos with default
visibility.
This ensures that the version compiled into the library isn't
accidentally hidden.
diff --git a/libcxx/include/string b/libcxx/include/string
index c13cefc..0f84d87 100644
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -4232,8 +4232,9 @@
_LIBCPP_FUNC_VIS wstring to_wstring(long double __val);
template<class _CharT, class _Traits, class _Allocator>
- const typename basic_string<_CharT, _Traits, _Allocator>::size_type
- basic_string<_CharT, _Traits, _Allocator>::npos;
+_LIBCPP_FUNC_VIS
+const typename basic_string<_CharT, _Traits, _Allocator>::size_type
+ basic_string<_CharT, _Traits, _Allocator>::npos;
template <class _CharT, class _Allocator>
struct _LIBCPP_TEMPLATE_VIS