PTR_ADD and NPTR_ADD for bfd.h

PTR_ADD and NPTR_ADD for bfd.h

This defines a couple of macros used to avoid ubsan complaints about
calculations involving NULL pointers.  PTR_ADD should be used in the
case where it is known that the offset is always zero with a NULL
pointer, and you'd like to know if a non-zero offset is ever used.
NPTR_ADD should be rarely used, but is defined for cases where a
non-zero offset is expected and should be ignored if the pointer is
NULL.

bfd/
	* bfd-in.h (PTR_ADD, NPTR_ADD): Define.
	* bfd-in2.h: Regenerate.
	* elf-eh-frame.c (adjust_eh_frame_local_symbols): Avoid NULL
	pointer calculations.
	* elflink.c (_bfd_elf_strip_zero_sized_dynamic_sections): Likewise.
	(bfd_elf_add_dt_needed_tag, elf_finalize_dynstr): Likewise.
	(elf_link_add_object_symbols, elf_link_input_bfd): Likewise.
	(bfd_elf_final_link, bfd_elf_gc_record_vtinherit): Likewise.
binutils/
	* objdump.c (disassemble_section): Use PTR_ADD for rel_ppend.