bfd/

bfd/
	* libbfd-in.h (_bfd_clear_contents): New prototype.
	* reloc.c (_bfd_clear_contents): New.
	* libbfd.h: Regenerated.

	* elf32-arm.c (elf32_arm_final_link_relocate): Use
	_bfd_clear_contents.
	* elf32-d10v.c (elf32_d10v_relocate_section): Likewise.
	* elf32-hppa.c (elf32_hppa_relocate_section): Likewise.
	* elf32-i386.c (elf_i386_relocate_section): Likewise.
	* elf32-ppc.c (ppc_elf_relocate_section): Likewise.
	* elf32-s390.c (elf_s390_relocate_section): Likewise.
	* elf32-sh.c (sh_elf_relocate_section): Likewise.
	* elf32-xtensa.c (elf_xtensa_relocate_section): Likewise.
	* elf64-ppc.c (ppc64_elf_relocate_section): Likewise.
	* elf64-s390.c (elf_s390_relocate_section): Likewise.
	* elf64-x86-64.c (elf64_x86_64_relocate_section): Likewise.
	* elfxx-sparc.c (_bfd_sparc_elf_relocate_section): Likewise.

	* elfxx-ia64.c (elfNN_ia64_relocate_section): Set value to
	zero for discarded symbols.
	* elfxx-mips.c (mips_elf_calculate_relocation): Likewise.
ld/testsuite/
	* ld-discard/zero-rel.d, ld-discard/zero-rel.s: New files.