x86: Properly handle __ehdr_start

x86: Properly handle __ehdr_start

After _bfd_i386_elf_convert_load and _bfd_x86_64_elf_convert_load are
removed, elf_i386_convert_load_reloc and elf_x86_64_convert_load_reloc
see __ehdr_start as an undefined symbol when they are called from
check_relocs to convert GOT relocations against local symbols.  But
__ehdr_start will be defined as a hidden symbol by linker at the later
stage if it is referenced.  This patch marks __ehdr_start as a defined
local symbol at the start of check_relocs if it is referenced and not
defined.

bfd/

	PR ld/22115
	* elf32-i386.c (elf_i386_convert_load_reloc): Check linker_def.
	Don't use UNDEFINED_WEAK_RESOLVED_TO_ZERO.
	* elf64-x86-64.c (elf_x86_64_convert_load_reloc): Check
	linker_def.  Don't use UNDEFINED_WEAK_RESOLVED_TO_ZERO.
	* elfxx-x86.c (_bfd_x86_elf_link_check_relocs): Set local_ref
	and linker_def on __ehdr_start if it is referenced and not
	defined.
	(_bfd_x86_elf_link_symbol_references_local): Also set local_ref
	and return TRUE when building executable, if a symbol has
	non-GOT/non-PLT relocations in text section or there is no
	dynamic linker.
	* elfxx-x86.h (elf_x86_link_hash_entry): Add linker_def.

ld/

	PR ld/22115
	* ld-i386/i386.exp: Run PR ld/22115 tests,
	* ld/testsuite/ld-x86-64/x86-64.exp: Likewise.
	* testsuite/ld-i386/pr22115-1.s: New file.
	* testsuite/ld-i386/pr22115-1a.d: Likewise.
	* testsuite/ld-i386/pr22115-1b.d: Likewise.
	* testsuite/ld-i386/pr22115-1c.d: Likewise.
	* testsuite/ld-i386/pr22115-1d.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1.s: Likewise.
	* testsuite/ld-x86-64/pr22115-1a-x32.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1a.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1b-x32.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1b.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1c-x32.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1c.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1d-x32.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1d.d: Likewise.