Activate turnstile on mainnet
This PR enables [ZIP209](https://github.com/zcash/zips/blob/master/zip-0209.rst) support on mainnet, to mark blocks as invalid if they would lead to a turnstile violation in the Sprout or Sapling value pools.
To test this PR, I performed the following manual tests:
1. Used RPC call `getblock` to verify the fallback Sprout value.
2. Individually changed the fallback Sprout block hash, block height and chain value, recompiling and relaunching the node, verifying that each individual change resulted in an error. When the block hash and block height are incorrect, an error is logged to debug.log `FallbackSproutValuePoolBalance(): fallback block hash is incorrect`. An incorrect chain value results in node termination with error: `void FallbackSproutValuePoolBalance(CBlockIndex*, const CChainParams&): Assertion '*pindex->nChainSproutValue == chainparams.SproutValuePoolCheckpointBalance()' failed.`
3. Ran the `Smoke Testing` described in PR #3885, on mainnet.
4. Launched zcashd with experimental feature `-developersetpoolsizezero` to manually trigger a turnstile violation in both Sprout and Sapling shielded pools. The Sprout turnstile violation occurred after launch, due to chance, when the next incoming block 520786 contained a Sprout unshielding transaction. The Sapling turnstile violation was triggered after creating a Sapling unshielding transaction.
add TimestampIndex changes needed for bitcore block explorer
Addresses #3708, follow-on to #3849, no tests yet. This is the third of 3 indices that we're adding.
add SpentIndex changes needed for bitcore block explorer
Addresses #3708, follow-on to #3837, note there are no tests yet (will come later with RPC interfaces).
init: Fix new HD seed generation for previously-encrypted wallets
Closes#3607.
How to verify (with `zcashd` flags `-testnet -wallet=wallet.3607.dat -experimentalfeatures -developerencryptwallet`):
- Start `zcashd` 2.0.0, encrypt the wallet, and stop the node.
- Start `zcashd` 2.0.1+ (before this branch), and see that it crashes during startup.
- Start `zcashd` built from this branch, and see that it does not crash during startup. Unlock the wallet, then stop.
- Start `zcashd` 2.0.1+ (before this branch), and see that it no longer crashes during startup.
Test turnstile violation
Adds experimental feature -developersetpoolsizezero to enable developers to test Sprout and Sapling turnstile violations on testnet and in regtest mode.
depends: Support additional cross-compilation targets in Rust
This will make it easier for third parties to cross-compile `zcashd` for other platforms. The third commit in this PR shows how to add a new target to the Rust dependency builder.
The default Rust target during cross-compilation is the canonical host, which is derived from `HOST` using `depends/config.sub`. If the canonical host differs from the required Rust target, add the necessary mapping in addition to the target itself.
Also includes fixes for cross-compiling aarch64 targets.
fix enable-debug build DB_COINS undefined
Fixes#3860. The way `DB_COINS` is defined in this PR is the same as in `src/txdb.cpp` (static "global" instead of class member).
Add Sprout support to TransactionBuilder
The logic in `TransactionBuilder::CreateJSDescriptions()` is a combination of the logic used by `z_sendmany`, `z_mergetoaddress` and `z_shieldcoinbase`, in order to support arbitrary numbers of Sprout inputs or outputs.
Eirik0