message: elle.log.Send: Fix windows UB.
diff: @@ -42,6 +42,7 @@ namespace elle
  // elle::print can throw, and it only throws elle::Error.
  catch (...)
  {
  + static boost::format const error("%s:%s: invalid log: %s");
  this->_send(Logger::Level::log,
  Logger::Type::error,
  false,
  @@ -49,7 +50,7 @@ namespace elle
  __FILE__,
  __LINE__,
  ELLE_COMPILER_PRETTY_FUNCTION,
  - elle::print("%s:%s: invalid log: %s", file, line, fmt)
  + str(boost::format(error) % file % line % fmt)
  );
  if (debug)
  throw;
  