* config/alpha/tm-alpha.h (EXTRA_FRAME_INFO): Add pc_reg field.

	* config/alpha/tm-alpha.h (EXTRA_FRAME_INFO):  Add pc_reg field.
	(SKIP_TRAMPOLINE_CODE):  Define.
	* alpha-tdep.c (alpha_frame_saved_pc):  Use pc_reg field from
	frame to find the saved pc register.
	(alpha_saved_pc_after_call):  Skip over shared library trampoline
	before trying to find the saved pc register.
	(find_proc_desc):  Copy PROC_PC_REG from found proc_desc
	to heuristic proc_desc.
	(init_extra_frame_info):  Initialize pc_reg field in frame.