fix build for macOS 10.13

This patch fix compile error: 'value' is unavailable: introduced
in macOS 10.14 when building for macOS 10.13

Change-Id: I1825c138d102531460759869426904a7da464a58

src/containerview.h

@@ -265,7 +265,16 @@ private:
     }
 
     // Hard unbox and unwrap underlying data container.
-    const BaseType& data() { return data_.value().get(); }
+    const BaseType& data() {
+        //this fix error when build for macOS 10.13(error: 'value' is unavailable: introduced in macOS 10.14)
+    #ifdef __APPLE__
+        if(!data_.has_value())
+           throw std::logic_error("bad optional access");
+        return *data_;
+    #else
+        return data_.value().get();
+    #endif
+    }
 
     // Actually filter the view.
     template<typename T, typename Func = FilterCallback>