Fix copying Solaris binaries with objcopy.

Fix copying Solaris binaries with objcopy.

	PR target/19938
bfd	* elf-bbfd.h (struct elf_backend_data): New field:
	elf_strtab_flags.
	New field: elf_backend_set_special_section_info_and_link
	* elfxx-target.h (elf_backend_strtab_flags): Define if not already
	defined.
	(elf_backend_set_special_section_info_and_link): Define if not
	already defined.
	(elfNN_bed): Use elf_backend_set_special_section_info_and_link and
	elf_backend_strtab_flags macros to initialise fields in structure.
	* elf.c (_bfd_elf_make_section_from_shdr): Check for SHF_STRINGS
	being set even if SHF_MERGE is not set.
	(elf_fake_sections): Likewise.
	(section_match): New function.  Matches two ELF sections based
	upon fixed characteristics.
	(find_link): New function.  Locates a section in a BFD that
	matches a section in a different BFD.
	(_bfd_elf_copy_private_bfd_data): Copy the sh_info and sh_link
	fields of reserved sections.
	(bfd_elf_compute_section_file_positions): Set the flags for the
	.shstrtab section based upon the elf_strtab_flags field in the
	elf_backend_data structure.
	(swap_out_syms): Likewise for the .strtab section.
	* elflink.c (bfd_elf_final_link): Set the flags for the
	.strtab section based upon the elf_strtab_flags field in the
	elf_backend_data structure.
	* elf32-i386.c (elf32_i386_set_special_info_link): New function.
	(elf_backend_strtab_flags): Set to SHF_STRINGS for Solaris
	targets.
	(elf_backend_set_special_section_info_and_link): Define for
	Solaris targets.
	* elf32-sparc.c: Likewise.
	* elf64-x86-64.c: Likewise.

binutils* testsuite/binutils-all/i386/compressed-1b.d: Allow for the
	string sections possibly having the SHF_STRINGS flag bit set.
	* testsuite/binutils-all/i386/compressed-1c.d: Likewise.
	* testsuite/binutils-all/readelf.s: Likewise.
	* testsuite/binutils-all/readelf.s-64: Likewise.
	* testsuite/binutils-all/x86-64/compressed-1b.d: Likewise.
	* testsuite/binutils-all/x86-64/compressed-1c.d: Likewise.

gas	* testsuite/gas/i386/ilp32/x86-64-unwind.d: Allow for the string
	sections possibly having the SHF_STRINGS flag bit set.
	* testsuite/gas/i386/x86-64-unwind.d: Likewise.