set Vdoc_cache_file and Vtexi_macros_file variables directly from command line options * octave.cc (octave_process_command_line): Set Vdoc_cache_file and Vtexi_macros_file directly. (octave_initialize_interpreter): Don't call bind_internal_variable to set Vdoc_cache_file or Vtexi_macros_file. (doc_cache_file, Vtexi_macros_file): Delete unused static variables. * defaults.cc (set_default_doc_cache_file): Don't set Vdoc_cache_file unless it is empty. (set_default_texi_macros_file): Don't set Vtexi_macros_file unless it is empty.