make: unifdef for other OSes (undefined)

*** 93,105 ****
          Name            done;
          Name            dot;
          Name            dot_keep_state;
          Name            dot_keep_state_file;
          Name            empty_name;
- #if defined(HP_UX) ||  defined(linux)
-         int             exit_status;
- #endif
          Boolean         fatal_in_progress;
          int             file_number;
  #if 0
          Boolean         filter_stderr;                  /* `-X' */
  #endif
--- 93,102 ----