* arm-tdep.c (arm_get_cache): Define.

	* arm-tdep.c (arm_get_cache): Define.
	(struct arm_prologue_cache): Renamed from frame_extra_info.  Add
	unwound_sp, unwound_pc, and saved_regs.
	(thumb_scan_prologue): Take a cache instead of the frame.
	(arm_scan_prologue): Likewise.
	(arm_frame_chain): Create a temporary cache for arm_scan_prologue
	instead of a temporary frame.
	(arm_init_extra_frame_info): Allocate and use a cache.
	(arm_frame_saved_pc, arm_pop_frame): Use the cache.