This changes anchor selection and Orchard authentication path generation
to default to select anchors at a the depth specified by the
`-orchardanchorconfirmations` CLI argument, with a default anchor
selection depth of 10 blocks.
If the value of `minconf` used for a particular call to `z_sendmany` is
less than the the set number of Orchard anchor confirmations, `minconf`
will be used instead for the Orchard anchor confirmations depth,
so that the selected anchor will be certain to contain any notes
selected to be spent.
Fixes#5644
This replaces the old implementation of asyncrpcoperation_sendmany
with one where all transaction construction is delegated to the
transaction builder. The capabilities of z_sendmany are somewhat
modified in the process:
* z_sendmany now permits sending funds from a Sprout address to
both transparent and Sapling addresses. PRIVACY NOTE: When
user sends a Sprout->Sapling transaction, the amount of the
transaction is publicly revealed.
* z_sendmany no longer supports transactions sending funds into
the Sprout pool, with the exception of change amounts when
sending from a Sprout address.
* When sending transparent coinbase funds to a set of shielded
addresses, the amount sent to recipients must fully consume
the input value and no change is permitted. This is a slightly
weaker constraint than was previously implemented; in the past,
only a single shielded recipient was allowed.
When using this special string as the from address, UTXOs from any
transparent addresses within the wallet will be used to fund the
transaction. Change outputs will be sent to a new transparent address,
as with any other spend of transparent funds.
Closeszcash/zcash#3640.