* Makefile.in (timevar.o): Depend on flags.h.
	* timevar.c (unused_stack_instances): New variable.
	(timevar_push): Take a timevar_stack_def from
	unused_stack_instances if available.
	(timevar_pop): Push the popped timevar_stack_def onto
	unused_stack_instances.
	(TIMEVAR_ENABLE): New macro.
	(timevar_def): Make standalone a 1-bit field.  Add field used.
	(get_time): Rename parameter to now.  Return after clearing it if
	not TIMEVAR_ENABLE.
	(init_timevar): Do nothing if not TIMEVAR_ENABLE.
	(timevar_pop): Likewise.
	(timevar_stop): Likewise.
	(timevar_push): Likewise.  Mark the timing variable as used.
	(timevar_start): Likewise.
	(timevar_print): Do nothing if not TIMEVAR_ENABLE.  Don't print
	timevars that were never used.

From-SVN: r33504