* basic-block.h: Give the BB flags enum a name, bb_flags.
	Add new flags BB_FORWARDER_BLOCK, and BB_NONTHREADABLE_BLOCK.
	* cfgcleanup.c (enum bb_flags): Remove here.
	(BB_FLAGS, BB_SET_FLAG, BB_CLEAR_FLAG): Remove.
	(notice_new_block): Set/test bb->flags instead of aux via BB_FLAGS.
	(update_forwarder_flag): Likewise.
	(thread_jump): Likewise.
	(try_forward_edges): Likewise.
	(try_optimize_cfg): Likewise.  Clear bb->flags before updating the
	forwarder flags.  Don't clear bb->aux for all basic blocks.  Only
	reset the BB_FORWARDER_BLOCK and BB_NONTHREADABLE_BLOCK flags.

From-SVN: r101876