t_flags_linker_so()

    DON'T call these methods (except get_version) after
    constructing a compiler instance or inside any other method.
    All methods, except update_executables() and find_executables(),
    may call the get_version() method.

    After constructing a compiler instance, always call customize(dist=None)
    method that finalizes compiler construction and makes the following
    attributes available:
      compiler_f77
      compiler_f90
      compiler_fix
      linker_so
      archiver
      ranlib
      libraries
      library_dirs
    Ú	config_fcNÚ