* dll.c (clear_dlls): Replace accessing list implemention details
with API function.
* gdbthread.h (get_first_thread): Declare.
* inferiors.c (for_each_inferior_with_data): New function.
(get_first_thread): New function.
(find_thread_ptid): Simplify.
(get_first_inferior): New function.
(clear_list): Delete.
(one_inferior_p): New function.
(clear_inferior_list): New function.
(clear_inferiors): Update.
* inferiors.h (for_each_inferior_with_data): Declare.
(clear_inferior_list): Declare.
(one_inferior_p): Declare.
(get_first_inferior): Declare.
* linux-low.c (linux_wait_for_event): Replace accessing list
implemention details with API function.
* server.c (target_running): Ditto.
(accumulate_file_name_length): New function.
(emit_dll_description): New function.
(handle_qxfer_libraries): Replace accessing list implemention
details with API function.
(handle_qxfer_threads_worker): New function.
(handle_qxfer_threads_proper): Replace accessing list implemention
details with API function.
(handle_query): Ditto.
(visit_actioned_threads_callback_ftype): New typedef.
(visit_actioned_threads_data): New struct.
(visit_actioned_threads): Rewrite to be find_inferior callback.
(resume): Call find_inferior.
(handle_status): Replace accessing list implemention
details with API function.
(process_serial_event): Replace accessing list implemention details
with API function.
* target.c (set_desired_inferior): Replace accessing list implemention
details with API function.
* tracepoint.c (same_process_p): New function.
(gdb_agent_about_to_close): Replace accessing list implemention
details with API function.
* win32-low.c (child_delete_thread): Replace accessing list
implemention details with API function.
(match_dll_by_basename): New function.
(dll_is_loaded_by_basename): New function.
(win32_ensure_ntdll_loaded): Replace accessing list implemention
details call to dll_is_loaded_by_basename.
Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.