Index: libcxx/include/__locale
===================================================================
--- libcxx/include/__locale
+++ libcxx/include/__locale
@@ -712,9 +712,9 @@
     static locale::id id;
 
 #ifdef _CACHED_RUNES
-    static const size_t table_size = _CACHED_RUNES;
+    static _LIBCPP_CONSTEXPR const size_t table_size = _CACHED_RUNES;
 #else
-    static const size_t table_size = 256;  // FIXME: Don't hardcode this.
+    static _LIBCPP_CONSTEXPR const size_t table_size = 256;  // FIXME: Don't hardcode this.
 #endif
     _LIBCPP_INLINE_VISIBILITY const mask* table() const  _NOEXCEPT {return __tab_;}
     static const mask* classic_table()  _NOEXCEPT;