Remove invalid .dynamic section with --only-keep-debug

Remove invalid .dynamic section with --only-keep-debug.

bfd/

	PR binutils/22101
	* elf.c (rewrite_elf_program_header): Remove the segment from
	output if all sections in input have been removed.

binutils/x

	PR binutils/22101
	* objcopy.c (strip_main): Also remove invalid .dynamic section
	with --only-keep-debug.
	(copy_main): Likewise.

bfd/elf.c

@@ -6721,6 +6721,11 @@ rewrite_elf_program_header (bfd *ibfd, bfd *obfd)
 	    }
 	}
 
+      /* Remove the segment from output if all sections in input have
+	 been removed.  */
+      if (first_section != NULL && section_count == 0)
+	continue;
+
       /* Allocate a segment map big enough to contain
 	 all of the sections we have selected.  */
       amt = sizeof (struct elf_segment_map);

binutils/objcopy.c

@@ -4206,6 +4206,8 @@ strip_main (int argc, char *argv[])
 	  break;
 	case OPTION_ONLY_KEEP_DEBUG:
 	  strip_symbols = STRIP_NONDEBUG;
+	  /* Also remove invalid .dynamic section.  */
+	  handle_remove_section_option (".dynamic");
 	  break;
 	case OPTION_KEEP_FILE_SYMBOLS:
 	  keep_file_symbols = 1;
@@ -4582,6 +4584,8 @@ copy_main (int argc, char *argv[])
 
 	case OPTION_ONLY_KEEP_DEBUG:
 	  strip_symbols = STRIP_NONDEBUG;
+	  /* Also remove invalid .dynamic section.  */
+	  handle_remove_section_option (".dynamic");
 	  break;
 
 	case OPTION_KEEP_FILE_SYMBOLS: