Check ELF relocs after opening all input files

Check ELF relocs after opening all input files

Delaying checking ELF relocations until opening all input files so
that symbol information is final when relocations are checked.  This
is only enabled for x86 targets.

bfd/

	* elf-bfd.h (_bfd_elf_link_check_relocs): New.
	* elflink.c (_bfd_elf_link_check_relocs): New function.
	(elf_link_add_object_symbols): Call _bfd_elf_link_check_relocs
	if check_relocs_after_open_input is FALSE.

include/

	* bfdlink.h (bfd_link_info): Add check_relocs_after_open_input.

ld/

	* emulparams/elf32_x86_64.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	New.
	* emulparams/elf_i386.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/elf_i386_be.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/elf_i386_chaos.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/elf_i386_ldso.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/elf_i386_vxworks.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/elf_x86_64.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emulparams/i386nto.sh (CHECK_RELOCS_AFTER_OPEN_INPUT):
	Likewise.
	* emultempl/elf32.em (gld${EMULATION_NAME}_before_parse):
	Set check_relocs_after_open_input to TRUE if
	CHECK_RELOCS_AFTER_OPEN_INPUT is yes.
	(gld${EMULATION_NAME}_after_open): Call
	_bfd_elf_link_check_relocs on all inputs if
	check_relocs_after_open_input is TRUE.