message: Fix for GCC / Linux build
  Add MapServerEvents BitStream include in event_gen/main.cpp
diff: @@ -38,6 +38,10 @@ void generate_cpp(const std::vector<DefFile> &files,const QString &group_name,co
  tgt_file.open(QFile::WriteOnly);
  QTextStream tgt_stream(&tgt_file);
  tgt_stream << "// THIS FILE WAS GENERATED, DO NOT EDIT\n";
  + if(group_name=="MapServerEvents")
  + {
  + tgt_stream << "#include \"BitStream.h\"\n";
  + }
  for(const DefFile &d : files)
  {
  tgt_stream << QString("#include \"%1\"\n\n").arg(d.source_name);
  