Issue 6378 - [emscripten] Make DependentString constexpr

test/compiled/String.cpp

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
-
+ *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #include <string>
 #include <gtest/gtest.h>
 #include "compiled/String.h"
 
 ABP_NS_USING
 
@@ skipping 183 matching lines @@
   EXPECT_FALSE(lexical_cast<bool>(ABP_TEXT("some-string"_str)));
   EXPECT_FALSE(lexical_cast<bool>(ABP_TEXT(""_str)));
   EXPECT_FALSE(lexical_cast<bool>(DependentString()));
 }
 
 TEST(TestStringLexicalCast, toOwnedString)
 {
   EXPECT_EQ(ABP_TEXT("some-string"_str), lexical_cast<OwnedString>(ABP_TEXT("some-string"_str)));
   EXPECT_EQ(ABP_TEXT(""_str), lexical_cast<OwnedString>(ABP_TEXT(""_str)));
 }