gcc-4.6 (Travis CI) does not support

Author: cdunn2001

include/json/writer.h

@@ -92,14 +92,16 @@ class JSON_API StreamWriterBuilder : public StreamWriter::Factory {
   /** \brief How to write comments.
    * Default: All
    */
-  StreamWriter::CommentStyle cs_ = StreamWriter::CommentStyle::All;
+  StreamWriter::CommentStyle cs_;
   /** \brief Write in human-friendly style.
 
       If "", then skip all indentation and newlines.
       In that case, you probably want CommentStyle::None also.
       Default: "\t"
   */
-  std::string indentation_ = "\t";
+  std::string indentation_;
+
+  StreamWriterBuilder();
 
   /// Do not take ownership of sout, but maintain a reference.
   StreamWriter* newStreamWriter(std::ostream* sout) const;

src/lib_json/json_writer.cpp

@@ -961,6 +961,10 @@ int MyStreamWriter::write(Value const& root)
 }
 StreamWriter::Factory::~Factory()
 {}
+StreamWriterBuilder::StreamWriterBuilder()
+  : cs_(StreamWriter::CommentStyle::All)
+  , indentation_("\t")
+{}
 StreamWriter* StreamWriterBuilder::newStreamWriter(std::ostream* stream) const
 {
   std::string colonSymbol = " : ";