AArch64: Add support for AArch64 EFI (efi-*-aarch64).

AArch64: Add support for AArch64 EFI (efi-*-aarch64).

This adds support for efi-*-aarch64 by virtue of adding a new PEI target
pei-aarch64-little.  This is not a full tagret and only exists to support EFI
at this time.

This means that this target does not support relocation processing and is mostly
a container format.

As such it's not valid for use with gas but only with objcopy.

Any magic number is based on the Microsoft PE specification [1].

[1] https://docs.microsoft.com/en-us/windows/win32/debug/pe-format

bfd/ChangeLog:

2021-10-21  Tamar Christina  <tamar.christina@arm.com>

	PR binutils/26218
	* .gitignore (pe-aarch64igen.c): New.
	* Makefile.am (pei-aarch64.lo, pe-aarch64igen.lo, pei-aarch64.c,
	pe-aarch64igen.c): Add support.
	* Makefile.in: Likewise.
	* bfd.c (bfd_get_sign_extend_vma): Add pei-aarch64-little.
	* coff-aarch64.c: New file.
	* coffcode.h (coff_set_arch_mach_hook, coff_set_flags,
	coff_write_object_contents) Add aarch64 (aarch64_pei_vec) support.
	* config.bfd: Likewise.
	* configure: Likewise.
	* configure.ac: Likewise.
	* libpei.h (GET_OPTHDR_IMAGE_BASE, PUT_OPTHDR_IMAGE_BASE,
	GET_OPTHDR_SIZE_OF_STACK_RESERVE, PUT_OPTHDR_SIZE_OF_STACK_RESERVE,
	GET_OPTHDR_SIZE_OF_STACK_COMMIT, PUT_OPTHDR_SIZE_OF_STACK_COMMIT,
	GET_OPTHDR_SIZE_OF_HEAP_RESERVE, PUT_OPTHDR_SIZE_OF_HEAP_RESERVE,
	GET_OPTHDR_SIZE_OF_HEAP_COMMIT, PUT_OPTHDR_SIZE_OF_HEAP_COMMIT,
	GET_PDATA_ENTRY, _bfd_peAArch64_bfd_copy_private_bfd_data_common,
	_bfd_peAArch64_bfd_copy_private_section_data,
	_bfd_peAArch64_get_symbol_info, _bfd_peAArch64_only_swap_filehdr_out,
	_bfd_peAArch64_print_private_bfd_data_common,
	_bfd_peAArch64i_final_link_postscript,
	_bfd_peAArch64i_only_swap_filehdr_out, _bfd_peAArch64i_swap_aouthdr_in,
	_bfd_peAArch64i_swap_aouthdr_out, _bfd_peAArch64i_swap_aux_in,
	_bfd_peAArch64i_swap_aux_out, _bfd_peAArch64i_swap_lineno_in,
	_bfd_peAArch64i_swap_lineno_out, _bfd_peAArch64i_swap_scnhdr_out,
	_bfd_peAArch64i_swap_sym_in, _bfd_peAArch64i_swap_sym_out,
	_bfd_peAArch64i_swap_debugdir_in, _bfd_peAArch64i_swap_debugdir_out,
	_bfd_peAArch64i_write_codeview_record,
	_bfd_peAArch64i_slurp_codeview_record,
	_bfd_peAArch64_print_ce_compressed_pdata): New.
	* peXXigen.c (_bfd_XXi_swap_aouthdr_in, _bfd_XXi_swap_aouthdr_out,
	pe_print_pdata, _bfd_XX_print_private_bfd_data_common,
	_bfd_XX_bfd_copy_private_section_data, _bfd_XXi_final_link_postscript):
	Support COFF_WITH_peAArch64,
	* pei-aarch64.c: New file.
	* peicode.h (coff_swap_scnhdr_in, pe_ILF_build_a_bfd, pe_ILF_object_p):
	Support COFF_WITH_peAArch64.
	(jtab): Add dummy entry that traps.
	* targets.c (aarch64_pei_vec): New.

binutils/ChangeLog:

2021-10-21  Tamar Christina  <tamar.christina@arm.com>

	PR binutils/26218
	* objcopy.c (convert_efi_target): Add efi-*-aarch64 support.
	* testsuite/binutils-all/aarch64/pei-aarch64-little.d: New test.
	* testsuite/binutils-all/aarch64/pei-aarch64-little.s: New test.

include/ChangeLog:

2021-10-21  Tamar Christina  <tamar.christina@arm.com>

	PR binutils/26218
	* coff/aarch64.h: New file.
	* coff/pe.h (IMAGE_FILE_MACHINE_ARM64): New.