re PR target/51345 ([avr] Devices with 8-bit SP need their own multilib(s))

re PR target/51345 ([avr] Devices with 8-bit SP need their own multilib(s))

contrib/
	PR target/51345
	* gcc_update (files_and_dependencies): Add
	gcc/config/avr/t-multilib, gcc/config/avr/multilib.h.

libgcc/
	PR target/51345
	* config/avr/lib1funcs.S: Remove FIXME comments.
	(SPEED_DIV): Depend on __AVR_HAVE_8BIT_SP__.
gcc/
	PR target/51345
	* config.gcc (tm_file target=avr]): Add avr/avr-multilib.h
	(tmake_file target=avr): Add avr/t-multilib.

	* config/avr/avr-c.c (avr_cpu_cpp_builtins): Use AVR_HAVE_8BIT_SP
	to built-in define __AVR_HAVE_8BIT_SP__, __AVR_HAVE_16BIT_SP__.
	* config/avr/genmultilib.awk: New file.
	* config/avr/t-multilib: New auto-generated file.
	* config/avr/multilib.h: New auto-generated file.
	* config/avr/t-avr (AVR_MCUS): New variable.
	(genopt.sh): Use it.
	(s-mlib): Depend on t-multilib.
	(t-multilib, multilib.h): New dependencies.
	(s-avr-mlib): New rule to build t-multilib, multilib.h from AVR_MCUS.
	(MULTILIB_OPTIONS): Remove.
	(MULTILIB_MATCHES): Remove.
	(MULTILIB_DIRNAMES): Remove.
	(MULTILIB_EXCEPTIONS): Remove:
	* config/avr/genopt.sh: Don't use hard coded file name;
	pass AVR_MCUS from t-avr instead.

From-SVN: r182797