objcopy.c: Fix bfd_copy_private_symbol_data on 32-bit hosts

Use long with bfd_copy_private_symbol_data to fix

.../binutils/objcopy.c: In
function ‘copy_object’:
.../binutils/objcopy.c:3383:17: error: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘long int’ [-Werror=sign-compare]
 3383 |   for (i = 0; i < symcount; i++)
      |                 ^

on 32-bit hosts.

	PR binutils/14493
	* objcopy.c (copy_object): Use long with
	bfd_copy_private_symbol_data.

binutils/objcopy.c

@@ -3380,8 +3380,8 @@ copy_object (bfd *ibfd, bfd *obfd, const bfd_arch_info_type *input_arch)
       symcount = filter_symbols (ibfd, obfd, osympp, isympp, symcount);
     }
 
-  for (i = 0; i < symcount; i++)
-    if (!bfd_copy_private_symbol_data (ibfd, osympp[i], obfd, osympp[i]))
+  for (long s = 0; s < symcount; s++)
+    if (!bfd_copy_private_symbol_data (ibfd, osympp[s], obfd, osympp[s]))
       {
 	status = 1;
 	return false;