Import latest fixes to libiberty from GCC.

PR lto/81968
	* simple-object-elf.c (simple_object_elf_copy_lto_debug_section):
	Keep names of removed global symbols.

	* simple-object-xcoff.c (simple_object_xcoff_find_sections):
	Improve .go_export csect handling.  Don't make assumptions
	on containing section or number of auxiliary entries.

	PR lto/81968
	* simple-object-elf.c (simple_object_elf_copy_lto_debug_section):
	Adjust field with for sh_type write, set SHF_EXCLUDE only for
	removed sections.

	PR lto/81925
	* simple-object-elf.c (simple_object_elf_write_shdr): Adjust
	type of sh_addralign and sh_entsize and properly write
	sh_entsize as Elf_Addr.
	(simple_object_elf_write_to_file): Read sh_entsize as Elf_Addr.

	* simple-object-common.h (struct simple_object_functions): Add
	copy_lto_debug_sections hook.
	* simple-object.c: Include fcntl.h.
	(handle_lto_debug_sections): New helper function.
	(simple_object_copy_lto_debug_sections): New function copying
	early LTO debug sections to regular debug sections in a new file.
	(simple_object_start_write): Handle NULL segment_name.
	* simple-object-coff.c (simple_object_coff_functions): Adjust
	for not implemented copy_lto_debug_sections hook.
	* simple-object-mach-o.c (simple_object_mach_o_functions): Likewise.
	* simple-object-xcoff.c (simple_object_xcoff_functions): Likewise.
	* simple-object-elf.c (SHT_NULL, SHT_SYMTAB, SHT_RELA, SHT_REL,
	SHT_GROUP): Add various sectopn header types.
	(SHF_EXCLUDE): Add flag.
	(Elf32_External_Sym, Elf64_External_Sym): Add symbol struct.
	(ELF_ST_BIND, ELF_ST_TYPE, ELF_ST_INFO): Add accessors.
	(STT_OBJECT, STT_FUNC, STT_TLS, STT_GNU_IFUNC): Add Symbol types.
	(STV_DEFAULT): Add symbol visibility.
	(SHN_COMMON): Add special section index name.
	(struct simple_object_elf_write): New.
	(simple_object_elf_start_write): Adjust for new private data.
	(simple_object_elf_write_shdr): Pass in values for all fields
	we write.
	(simple_object_elf_write_to_file): Adjust.  Copy from recorded
	section headers if requested.
	(simple_object_elf_release_write): Release private data.
	(simple_object_elf_copy_lto_debug_sections): Copy and rename sections
	as denoted by PFN and all their dependences, symbols and relocations
	to the empty destination file.
	(simple_object_elf_functions): Adjust for copy_lto_debug_sections hook.

	* simple-object-xcoff.c (simple_object_xcoff_find_sections):
	Search symbol table for .go_export symbol and apply pfn if found.

libiberty/simple-object.c

@@ -22,6 +22,7 @@ Boston, MA 02110-1301, USA.  */
 #include "simple-object.h"
 
 #include <errno.h>
+#include <fcntl.h>
 
 #ifdef HAVE_STDLIB_H
 #include <stdlib.h>
@@ -249,6 +250,86 @@ simple_object_find_section (simple_object_read *sobj, const char *name,
   return 1;
 }
 
+/* Callback to identify and rename LTO debug sections by name.
+   Returns 1 if NAME is a LTO debug section, 0 if not.  */
+
+static int
+handle_lto_debug_sections (const char **name)
+{
+  /* ???  So we can't use .gnu.lto_ prefixed sections as the assembler
+     complains about bogus section flags.  Which means we need to arrange
+     for that to be fixed or .gnu.debuglto_ marked as SHF_EXCLUDE (to make
+     fat lto object tooling work for the fat part).  */
+  /* ???  For now this handles both .gnu.lto_ and .gnu.debuglto_ prefixed
+     sections.  */
+  /* Copy LTO debug sections and rename them to their non-LTO name.  */
+  if (strncmp (*name, ".gnu.debuglto_", sizeof (".gnu.debuglto_") - 1) == 0)
+    {
+      *name = *name + sizeof (".gnu.debuglto_") - 1;
+      return 1;
+    }
+  else if (strncmp (*name, ".gnu.lto_.debug_", sizeof (".gnu.lto_.debug_") -1) == 0)
+    {
+      *name = *name + sizeof (".gnu.lto_") - 1;
+      return 1;
+    }
+  return 0;
+}
+
+/* Copy LTO debug sections.  */
+
+const char *
+simple_object_copy_lto_debug_sections (simple_object_read *sobj,
+				       const char *dest, int *err)
+{
+  const char *errmsg;
+  simple_object_write *dest_sobj;
+  simple_object_attributes *attrs;
+  int outfd;
+
+  if (! sobj->functions->copy_lto_debug_sections)
+    {
+      *err = EINVAL;
+      return "simple_object_copy_lto_debug_sections not implemented";
+    }
+
+  attrs = simple_object_fetch_attributes (sobj, &errmsg, err);
+  if (! attrs)
+    return errmsg;
+  dest_sobj = simple_object_start_write (attrs, NULL, &errmsg, err);
+  simple_object_release_attributes (attrs);
+  if (! dest_sobj)
+    return errmsg;
+
+  errmsg = sobj->functions->copy_lto_debug_sections (sobj, dest_sobj,
+						     handle_lto_debug_sections,
+						     err);
+  if (errmsg)
+    {
+      simple_object_release_write (dest_sobj);
+      return errmsg;
+    }
+
+  outfd = creat (dest, 00777);
+  if (outfd == -1)
+    {
+      *err = errno;
+      simple_object_release_write (dest_sobj);
+      return "open failed";
+    }
+
+  errmsg = simple_object_write_to_file (dest_sobj, outfd, err);
+  close (outfd);
+  if (errmsg)
+    {
+      simple_object_release_write (dest_sobj);
+      return errmsg;
+    }
+
+  simple_object_release_write (dest_sobj);
+  return NULL;
+}
+
 /* Fetch attributes.  */
 
 simple_object_attributes *
@@ -315,7 +396,7 @@ simple_object_start_write (simple_object_attributes *attrs,
     return NULL;
   ret = XNEW (simple_object_write);
   ret->functions = attrs->functions;
-  ret->segment_name = xstrdup (segment_name);
+  ret->segment_name = segment_name ? xstrdup (segment_name) : NULL;
   ret->sections = NULL;
   ret->last_section = NULL;
   ret->data = data;