Properly handle relocs against absolute symbols

Relocations against absolute symbols in shared object should be resolved
at link-time if symbols are bounded locally.  For PC-relative relocation
against absolute symbols, they should be converted to non-PC-relative
relocation in target backend.  If conversion can't be performed, target
backend should detect it and issue an error.  This patch only fixes x86
backends.

bfd/

	PR ld/19818
	* bfd-in.h (bfd_elf_record_link_assignment): Add a bfd_boolean.
	* bfd-in2.h: Regenerated.
	* elf-bfd.h (elf_link_hash_entry): Add def_linker and
	def_linker_abs.
	(RESOLVED_TO_ABS_IN_PIC): New macro.
	* elf32-i386.c (RESOLVED_TO_ZERO_OR_ABS): New macro.
	(elf_i386_allocate_dynrelocs): Replace
	UNDEFINED_WEAK_RESOLVED_TO_ZERO with RESOLVED_TO_ZERO_OR_ABS.
	Discard space for non-pc-relative relocs against symbols which
	are always resolved at link-time.
	(elf_i386_convert_load): Replace UNDEFINED_WEAK_RESOLVED_TO_ZERO
	with RESOLVED_TO_ZERO_OR_ABS.
	(elf_i386_relocate_section): Replace
	UNDEFINED_WEAK_RESOLVED_TO_ZERO with RESOLVED_TO_ZERO_OR_ABS.
	Properly handle R_386_32 relocation against absolute symbol.
	* elf64-x86-64.c (RESOLVED_TO_ZERO_OR_ABS): New macro.
	(elf_x86_64_need_pic): Updated to check absolute symbol.
	(elf_x86_64_check_relocs): Don't check R_X86_64_32 nor
	R_X86_64_32S in shared object here.  Use elf_x86_64_need_pic.
	(elf_x86_64_allocate_dynrelocs): Replace
	UNDEFINED_WEAK_RESOLVED_TO_ZERO with RESOLVED_TO_ZERO_OR_ABS.
	Discard space for non-pc-relative relocs against symbols which
	are always resolved at link-time.
	(elf_x86_64_convert_load): Replace UNDEFINED_WEAK_RESOLVED_TO_ZERO
	with RESOLVED_TO_ZERO_OR_ABS.  Check def_linker for linker
	defined symbol.
	(elf_x86_64_relocate_section): Replace
	UNDEFINED_WEAK_RESOLVED_TO_ZERO with RESOLVED_TO_ZERO_OR_ABS.
	Properly handle R_X86_64_PC32, R_X86_64_32, R_X86_64_32S amd
	R_X86_64_64 relocations against absolute symbol.
	* elflink.c (bfd_elf_record_link_assignment): Updated.  Set
	def_linker and defsym.

ld/

	PR ld/19818
	* emultempl/elf32.em (gld${EMULATION_NAME}_find_exp_assignment):
	Pass "exp->assign.defsym || !expld.rel_from_abs" to
	bfd_elf_record_link_assignment.
	(gld${EMULATION_NAME}_before_allocation): Set def_linker for
	"__ehdr_start".
	* testsuite/ld-i386/i386.exp: Run PR ld/19818 tests.
	* testsuite/ld-x86-64/x86-64.exp: Likewise.
	* testsuite/ld-elf/pr19818a.d: New file.
	* testsuite/ld-elf/pr19818a.s: Likewise.
	* testsuite/ld-elf/pr19818b.d: Likewise.
	* testsuite/ld-elf/pr19818b.s: Likewise.
	* testsuite/ld-i386/pr19818-1.t: Likewise.
	* testsuite/ld-i386/pr19818-1a.d: Likewise.
	* testsuite/ld-i386/pr19818-1a.s: Likewise.
	* testsuite/ld-i386/pr19818-1b.d: Likewise.
	* testsuite/ld-i386/pr19818-1b.s: Likewise.
	* testsuite/ld-i386/pr19818-1c.d: Likewise.
	* testsuite/ld-i386/pr19818-1c.s: Likewise.
	* testsuite/ld-i386/pr19818-1d.d: Likewise.
	* testsuite/ld-i386/pr19818-1e.d: Likewise.
	* testsuite/ld-i386/pr19818-1f.d: Likewise.
	* testsuite/ld-i386/pr19818-1g.d: Likewise.
	* testsuite/ld-i386/pr19818-1h.d: Likewise.
	* testsuite/ld-i386/pr19818-1i.d: Likewise.
	* testsuite/ld-i386/pr19818-1j.d: Likewise.
	* testsuite/ld-i386/pr19818-1k.d: Likewise.
	* testsuite/ld-i386/pr19818-1l.d: Likewise.
	* testsuite/ld-i386/pr19818-2.s: Likewise.
	* testsuite/ld-i386/pr19818-2a.d: Likewise.
	* testsuite/ld-i386/pr19818-2b.d: Likewise.
	* testsuite/ld-i386/pr19818-2c.d: Likewise.
	* testsuite/ld-i386/pr19818-2d.d: Likewise.
	* testsuite/ld-i386/pr19818-2e.d: Likewise.
	* testsuite/ld-i386/pr19818-2f.d: Likewise.
	* testsuite/ld-i386/pr19818-2g.d: Likewise.
	* testsuite/ld-i386/pr19818-2h.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1.t: Likewise.
	* testsuite/ld-x86-64/pr19818-1a.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1a.s: Likewise.
	* testsuite/ld-x86-64/pr19818-1b.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1b.s: Likewise.
	* testsuite/ld-x86-64/pr19818-1c.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1c.s: Likewise.
	* testsuite/ld-x86-64/pr19818-1d.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1e.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1f.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1g.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1h.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1i.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1j.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1k.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1l.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1m.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1n.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1o.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1p.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1q.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1r.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1s.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1t.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1u.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1v.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1w.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1x.d: Likewise.
	* testsuite/ld-x86-64/pr19818-1y.d: Likewise.
	* testsuite/ld-x86-64/pr19818-2.s: Likewise.
	* testsuite/ld-x86-64/pr19818-2a.d: Likewise.
	* testsuite/ld-x86-64/pr19818-2b.d: Likewise.
	* testsuite/ld-x86-64/pr19818-2c.d: Likewise.
	* testsuite/ld-x86-64/pr19818-2d.d: Likewise.
	* testsuite/ld-x86-64/pr19818-3.s: Likewise.
	* testsuite/ld-x86-64/pr19818-3a.d: Likewise.
	* testsuite/ld-x86-64/pr19818-3b.d: Likewise.
	* testsuite/ld-x86-64/pr19818-3c.d: Likewise.
	* testsuite/ld-x86-64/pr19818-3d.d: Likewise.
	* testsuite/ld-x86-64/pr19818-4.s: Likewise.
	* testsuite/ld-x86-64/pr19818-4a.d: Likewise.
	* testsuite/ld-x86-64/pr19818-4b.d: Likewise.
	* testsuite/ld-x86-64/pr19818-5.s: Likewise.
	* testsuite/ld-x86-64/pr19818-5a.d: Likewise.
	* testsuite/ld-x86-64/pr19818-5b.d: Likewise.