* doc/extend.texi (AVR Built-in Functions): Document
	__builtin_avr_flash_segment.
	* config/avr/builtins.def (__builtin_avr_flash_segment): New entry.
	* config/avr/avr.md (flash_segment, flash_segment1): New expanders.
	(*split.flash_segment): New insn-and-split.
	* config/avr/avr.c (avr_init_builtins): Add local variables:
	const_memx_void_node, const_memx_ptr_type_node,
	char_ftype_const_memx_ptr.

From-SVN: r184746