RISC-V: Merge ELF attribute for ld.

RISC-V: Merge ELF attribute for ld.

	2019-01-16  Kito Cheng  <kito@andestech.com>
		    Nelson Chu  <nelson@andestech.com>

	bfd/
	* elfnn-riscv.c (in_subsets): New.
	(out_subsets): Likewise.
	(merged_subsets): Likewise.
	(riscv_std_ext_p): Likewise.
	(riscv_non_std_ext_p): Likewise.
	(riscv_std_sv_ext_p): Likewise.
	(riscv_non_std_sv_ext_p): Likewise.
	(riscv_version_mismatch): Likewise.
	(riscv_i_or_e_p): Likewise.
	(riscv_merge_std_ext): Likewise.
	(riscv_merge_non_std_and_sv_ext): Likewise.
	(riscv_merge_arch_attr_info): Likewise.
	(riscv_merge_attributes): Likewise.
	(_bfd_riscv_elf_merge_private_bfd_data): Merge attribute.
	ld/
	* testsuite/ld-elf/orphan-region.d: XFAIL for RISC-V, because add new
	section.
	* testsuite/ld-riscv-elf/ld-riscv-elf.exp: Add new tests.
	* testsuite/ld-riscv-elf/attr-merge-arch-01.d: New test.
	* testsuite/ld-riscv-elf/attr-merge-arch-01a.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-arch-01b.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-arch-02.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-arch-02a.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-arch-02b.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-arch-03.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-arch-03a.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-arch-03b.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-arch-failed-01.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-arch-failed-01a.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-arch-failed-01b.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-priv-spec-a.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-priv-spec-b.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-priv-spec.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-stack-align-a.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-stack-align-b.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-stack-align-failed-a.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-stack-align-failed-b.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-stack-align-failed.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-stack-align.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-strict-align-01.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-strict-align-01a.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-strict-align-01b.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-strict-align-02.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-strict-align-02a.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-strict-align-02b.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-strict-align-03.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-strict-align-03a.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-strict-align-03b.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-strict-align-04.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-strict-align-04a.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-strict-align-04b.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-strict-align-05.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-strict-align-05a.s: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-strict-align-05b.s: Likewise.