* ui-file.h (ui_file_xstrdup): Mention that the length argument

	* ui-file.h (ui_file_xstrdup): Mention that the length argument
	may be NULL.
	* ui-file.c (ui_file_xstrdup): Don't dereference LENGTH if it is
	NULL.
	* aix-thread.c (aix_thread_extra_thread_info): Pass NULL as length
	parameter to ui_file_xstrdup.
	* arm-tdep.c (_initialize_arm_tdep): Ditto.
	* infrun.c (print_target_wait_results): Ditto.
	* language.c (add_language): Ditto.
	* linespec.c (cplusplus_error): Ditto.
	* remote.c (escape_buffer): Ditto.
	* typeprint.c (type_to_string): Ditto.
	* utils.c (error_stream): Ditto.
	* varobj.c (value_get_print_value): Ditto.
	* xtensa-tdep.c (xtensa_verify_config): Replace `dummy' local with
	`length' local.  Pass it to ui_file_xstrdup, and avoid an strlen
	call.
	* gdbarch.sh (verify_gdbarch): Ditto.
	* gdbarch.c: Regenerate.
	* cli/cli-setshow.c (do_setshow_command): Pass NULL as length
	parameter to ui_file_xstrdup.
	* python/python-frame.c (frapy_str): Ditto.
	* python/python-type.c (typy_str): Use the length local instead of
	calling strlen.
	* python/python-value.c (valpy_str): Pass NULL as length parameter
	to ui_file_xstrdup.