* config/xtensa/unwind-dw2-xtensa.c: New.
	* config/xtensa/unwind-dw2-xtensa.h: New.
	* config/xtensa/xtensa.h (MUST_USE_SJLJ_EXCEPTIONS): Remove.
	(DWARF2_UNWIND_INFO): Remove.
	(DWARF_FRAME_REGISTERS): Define.
	(EH_RETURN_DATA_REGNO): Define.
	* config/xtensa/xtensa.md (UNSPECV_EH_RETURN): Define.
	(eh_return): New.
	* config/xtensa/t-xtensa (LIB2ADDEH): Define.

Co-Authored-By: Bob Wilson <bob.wilson@acm.org>

From-SVN: r130160