We do this a lot, and had boutique helpers in various places. So add
a more generic one; for convenience it returns a pointer to the new
end element.
I prefer the name tal_arr_expand to tal_arr_append, since it's up to
the caller to populate the new array entry.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
tal_count() is used where there's a type, even if it's char or u8, and
tal_bytelen() is going to replace tal_len() for clarity: it's only needed
where a pointer is void.
We shim tal_bytelen() for now.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Rusty Russell