libarchive: Avoid declaration after statement in C code

Utilities/cmlibarchive/libarchive/archive_write_set_format_iso9660.c

@@ -4074,8 +4074,10 @@ write_information_block(struct archive_write *a)
 	memset(info.s, 0, info_size);
 	opt = 0;
 #if defined(HAVE__CTIME64_S)
-	__time64_t iso9660_birth_time_tmp = (__time64_t) iso9660->birth_time; //time_t may be shorter than 64 bits
-	_ctime64_s(buf, sizeof(buf), &(iso9660_birth_time_tmp));
+	{
+		__time64_t iso9660_birth_time_tmp = (__time64_t) iso9660->birth_time; //time_t may be shorter than 64 bits
+		_ctime64_s(buf, sizeof(buf), &(iso9660_birth_time_tmp));
+	}
 #elif defined(HAVE_CTIME_R)
 	ctime_r(&(iso9660->birth_time), buf);
 #else