the mksquashfs code has an all_zeros func that does:
long *p = (long *) file_buffer->data;
make sure we force the data field to be aligned so that still works.
--- a/squashfs-tools/caches-queues-lists.h+++ b/squashfs-tools/caches-queues-lists.h@@ -123,6 +123,7 @@ struct file_buffer { char locked;
char wait_on_unlock;
char noD;
+ long _pad; char data[0];
};