gdb/

gdb/
	* cli/cli-decode.c (add_setshow_zuinteger_unlimited_cmd): New.
	Update comment to add_setshow_integer_cmd.
	* cli/cli-setshow.c (do_set_command): Handle case
	'var_zuinteger_unlimited'.
	(do_show_command): Likewise.
	* cli/cli-cmds.c (init_cmds): Call add_setshow_zuinteger_unlimited_cmd
	for command 'remotetimeout'.
	* command.h (enum var_types): New zuinteger_unlimited.  Update comment
	to var_integer.
	* source.c (_initialize_source): Call add_setshow_zuinteger_unlimited_cmd
	for command 'set listsize'.

gdb/doc/
	* gdb.texinfo (List): Describe the meaning of 0 and -1 in
	'set listsize'.

gdb/testsuite/
	* gdb.base/list.exp (set_listsize): Don't set arg to "unlimited"
	when it is less than 0.