devel/binutils: Setting sh_link for SHT_REL/SHT_RELA

Import upstream commit 6b958fe36b7:

It's wrong to have an alloc reloc section trying to use a non-alloc
symbol table.

	* elf.c (assign_section_numbers <SHT_REL, SHT_RELA>): Correct
	comment.  Always set sh_link to .dynsym for alloc reloc
	sections and to .symtab for non-alloc.

This also fixes strip when using llvm-strip, i.e. when base built with
WITH_LLVM_BINUTILS.

PR:		271061, see also: 270961, 270960
Reported by:	Emanuel Haupt <ehaupt@FreeBSD.org>
Approved by:	cy
Obtained from:	Upstream commit 6b958fe36b7
MFH:		2022Q2

devel/binutils/Makefile

@@ -1,6 +1,6 @@
 PORTNAME=	binutils
 DISTVERSION=	2.40
-PORTREVISION=	2
+PORTREVISION=	3
 PORTEPOCH?=	1
 CATEGORIES?=	devel
 MASTER_SITES=	SOURCEWARE/binutils/releases

devel/binutils/files/patch-bfd_elf.c

@@ -0,0 +1,39 @@
+--- bfd/elf.c.orig	2023-01-14 00:00:00 UTC
++++ bfd/elf.c
+@@ -3870,21 +3870,23 @@ assign_section_numbers (bfd *abfd, struct bfd_link_inf
+ 	{
+ 	case SHT_REL:
+ 	case SHT_RELA:
+-	  /* A reloc section which we are treating as a normal BFD
+-	     section.  sh_link is the section index of the symbol
+-	     table.  sh_info is the section index of the section to
+-	     which the relocation entries apply.  We assume that an
+-	     allocated reloc section uses the dynamic symbol table
+-	     if there is one.  Otherwise we guess the normal symbol
+-	     table.  FIXME: How can we be sure?  */
+-	  if (d->this_hdr.sh_link == 0 && (sec->flags & SEC_ALLOC) != 0)
++	  /* sh_link is the section index of the symbol table.
++	     sh_info is the section index of the section to which the
++	     relocation entries apply.  */
++	  if (d->this_hdr.sh_link == 0)
+ 	    {
+-	      s = bfd_get_section_by_name (abfd, ".dynsym");
+-	      if (s != NULL)
+-		d->this_hdr.sh_link = elf_section_data (s)->this_idx;
++	      /* FIXME maybe: If this is a reloc section which we are
++		 treating as a normal section then we likely should
++		 not be assuming its sh_link is .dynsym or .symtab.  */
++	      if ((sec->flags & SEC_ALLOC) != 0)
++		{
++		  s = bfd_get_section_by_name (abfd, ".dynsym");
++		  if (s != NULL)
++		    d->this_hdr.sh_link = elf_section_data (s)->this_idx;
++		}
++	      else
++		d->this_hdr.sh_link = elf_onesymtab (abfd);
+ 	    }
+-	  if (d->this_hdr.sh_link == 0)
+-	    d->this_hdr.sh_link = elf_onesymtab (abfd);
+
+ 	  s = elf_get_reloc_section (sec);
+ 	  if (s != NULL)