code: def compiler():
      
      cfg_cxx = str(cfg.get('compiler', 'CXX'))
      if not cfg_cxx:
          cfg_cxx = None
      return os.environ.get('CXX', cfg_cxx) or None
docs: Get compiler to use for C++ to binary process. The precedence for
      choosing the compiler is as follows::
  
        1. `CXX` environment variable
        2. User configuration (~/.pythranrc)
  
      Returns None if none is set or if it's set to the empty string