gcc/ChangeLog:

	* config/riscv/riscv.h (RISCV_DWARF_VLENB): New.
	(DWARF_FRAME_REGISTERS): New.
	(DWARF_REG_TO_UNWIND_COLUMN): New.

libgcc/ChangeLog:

	* config.host (riscv*-*-*): Add config/riscv/value-unwind.h.
	* config/riscv/value-unwind.h: New.