message: Exclude expand_path when INSTALL is not defined
diff: // Copyright (c) 2015 Ville Voutilainen
  // Copyright (c) 2016 Alexander Kormanovsky
  // Copyright (c) 2016, 2017 Jiangang Zhuang
  +// Copyright (c) 2017 Nicolas Veloz Savino
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  @@ -189,6 +190,7 @@ get_download_folder()
  #else // !_WIN32
  +# ifndef INSTALL
  static
  std::string
  @@ -206,6 +208,8 @@ expand_path(std::string path)
  # endif
  }
  +# endif // !INSTALL
  +
  #endif // !_WIN32
  namespace date
  