options.texi (Variable): Document.

options.texi (Variable): Document.

	* doc/options.texi (Variable): Document.
	* optc-gen.awk, opth-gen.awk: Handle Variable records.  Don't
	generate target_flags declarations explicitly.  Don't define
	VarExists variables for the driver.
	* common.opt (target_flags): New Variable record.
	(flag_dump_unnumbered, flag_dump_unnumbered_links,
	flag_var_tracking, flag_var_tracking_assignments,
	flag_var_tracking_assignments_toggle): Don't mark variables with
	VarExists.
	* config/i386/i386.c (ix86_isa_flags): Don't define here.
	* config/i386/i386.opt (ix86_isa_flags): Define here.
	* config/mcore/mcore.c (mcore_stack_increment): Don't define here.
	* config/mcore/mcore.opt (mcore_stack_increment): Don't mark with
	VarExists.
	* flags.h (flag_dump_unnumbered, flag_var_tracking): Remove.
	* print-rtl.c (flag_dump_unnumbered, flag_dump_unnumbered_links):
	Only define for generator programs.
	* rtlanal.c (target_flags): Remove.
	* toplev.c (flag_var_tracking, flag_var_tracking_assignments,
	flag_var_tracking_assignments_toggle): Remove.

From-SVN: r164370