builtins.def (DEF_BUILTIN): Factor out "__builtin_avr_" from NAME, turn NAME to an...

builtins.def (DEF_BUILTIN): Factor out "__builtin_avr_" from NAME, turn NAME to an uppercase identifier.

	* config/avr/builtins.def (DEF_BUILTIN): Factor out
	"__builtin_avr_" from NAME, turn NAME to an uppercase identifier.
	Factor out 'CODE_FOR_' from ICODE, use 'nothing' instead of '-1'.
	Remove ID.  Adjust comments.
	* config/avr/avr-c.c (avr_builtin_name): Remove.
	(avr_cpu_cpp_builtins): Use DEF_BUILTIN instead of for-loop.
	* config/avr/avr.c (avr_tolower): New static function.
	(DEF_BUILTIN): Remove parameter ID.  Prefix ICODE by 'CODE_FOR_'.
	Stringify NAME, prefix it with "__builtin_avr_" and lowercase it.
	(avr_expand_builtin): Assert insn_code != CODE_FOR_nothing for
	default expansion.

From-SVN: r195276