* dwarf2.h (DW_CFA_GNU_negative_offset_extended): New constant.
* dwarf2out.c (dwarf_cfi_name): Print name of new constant.
(reg_save): Use DW_CFA_GNU_negative_offset_extended when needed.
(output_cfi): Handle output of DW_CFA_GNU_negative_offset_extended.
* frame.c (execute_cfa_insn): Handle
DW_CFA_GNU_negative_offset_extended.

From-SVN: r31858