(Vmac_ts_active_input_buf) [USE_MAC_TSM]: Add extern.

(Vmac_ts_active_input_buf) [USE_MAC_TSM]: Add extern.
(fast_find_position, x_y_to_hpos_vpos, mac_ax_selected_text_range):
(mac_ax_number_of_characters): Add externs.
(mac_get_selected_range, mac_store_buffer_text_to_unicode_chars)
[USE_MAC_TSM]: Likewise.
(mac_handle_text_input_event) [MAC_OSX]:
Handle kEventTextInputOffsetToPos for no active input area case.
Handle kEventTextInputPosToOffset and kEventTextInputGetSelectedText.
(mac_handle_document_access_event)
[MAC_OS_X_VERSION_MAX_ALLOWED >= 1030]: New function.
(install_application_handler) [MAC_OSX]: Register handlers for
kEventTextInputPosToOffset and kEventTextInputGetSelectedText.
(install_application_handler) [MAC_OS_X_VERSION_MAX_ALLOWED >= 1030]:
Register mac_handle_document_access_event.