gdb/

	gdb/
	* dwarf2loc.c (read_pieced_value): Handle get_frame_register_bytes
	returning that the register piece is unavailable/optimized out.
	(write_pieced_value): Handle get_frame_register_bytes returning
	that the register piece is unavailable/optimized out when doing a
	read-modify write of a bitfield.
	* findvar.c (value_from_register): Handle get_frame_register_bytes
	returning that the register piece is unavailable/optimized out.
	* frame.c (get_frame_register_bytes): New parameters `optimizedp'
	and `unavailablep'.  Throw error on bad debug info.  Use
	frame_register instead of frame_register_read, to fill in the new
	arguments.
	* frame.h (get_frame_register_bytes): New parameters `optimizedp'
	and `unavailablep'.
	* valops.c: (value_assign): Adjust, and handle
	get_frame_register_bytes failing.
	* spu-tdep.c: Include exceptions.h.
	(spu_software_single_step): Adjust, and handle
	get_frame_register_bytes failing.
	(spu_get_longjmp_target): Ditto.
	* gdbarch.sh (register_to_value): Change to return int.  New
	parameters `optimizedp' and `unavailablep'.
	* gdbarch.h, gdbarch.c: Regenerate.
	* i386-tdep.c (i386_register_to_value): Adjust to new
	gdbarch_register_to_value interface.
	* i387-tdep.c (i387_register_to_value): Ditto.
	* i387-tdep.h (i387_register_to_value): Ditto.
	* alpha-tdep.c (alpha_register_to_value): Ditto.
	* ia64-tdep.c (ia64_register_to_value): Ditto.
	* m68k-tdep.c (m68k_register_to_value): Ditto.
	* mips-tdep.c (mips_register_to_value): Ditto.
	* rs6000-tdep.c (rs6000_register_to_value): Ditto.