*: change execl sentinels from NULL to (char*)0

Signed-off-by: Rich Felker <dalias@aerifal.cx>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

archival/libarchive/data_extract_to_command.c

@@ -103,7 +103,7 @@ void FAST_FUNC data_extract_to_command(archive_handle_t *archive_handle)
 				archive_handle->tar__to_command_shell,
 				"-c",
 				archive_handle->tar__to_command,
-				NULL);
+				(char *)0);
 			bb_perror_msg_and_die("can't execute '%s'", archive_handle->tar__to_command_shell);
 		}
 		close(p[0]);