Merge #19299: refactor: Remove unused vars, Add missing includes

fa193c6 Add missing includes to fix compile errors (MarcoFalke)
fa09ec8 Remove unused variables (MarcoFalke)

Pull request description:

  This is required for #19183, but seems like good cleanup that can go in upfront.

ACKs for top commit:
  practicalswift:
    ACK fa193c6 -- patch looks correct
  hebasto:
    ACK fa193c6, I have reviewed the code and it looks OK, I agree it can be merged.

Tree-SHA512: 79b94e7f7ee3a1a8a8fb2ea1ecdf61f130f8b133a37865894da3dbbbf311979e7d1fc013b923fdd7dbf19a221e0232f664defbdb57aa44e0b8c45bfff3c71dcb

Author: fanquake

src/fs.cpp

@@ -5,10 +5,12 @@
 #include <fs.h>
 
 #ifndef WIN32
+#include <cstring>
 #include <fcntl.h>
 #include <string>
 #include <sys/file.h>
 #include <sys/utsname.h>
+#include <unistd.h>
 #else
 #ifndef NOMINMAX
 #define NOMINMAX
@@ -31,7 +33,8 @@ FILE *fopen(const fs::path& p, const char *mode)
 
 #ifndef WIN32
 
-static std::string GetErrorReason() {
+static std::string GetErrorReason()
+{
     return std::strerror(errno);
 }
 

src/interfaces/chain.h

@@ -8,6 +8,7 @@
 #include <optional.h>               // For Optional and nullopt
 #include <primitives/transaction.h> // For CTransactionRef
 
+#include <functional>
 #include <memory>
 #include <stddef.h>
 #include <stdint.h>

src/qt/coincontroldialog.cpp

@@ -400,7 +400,6 @@ void CoinControlDialog::updateLabels(CCoinControl& m_coin_control, WalletModel *
     // nPayAmount
     CAmount nPayAmount = 0;
     bool fDust = false;
-    CMutableTransaction txDummy;
     for (const CAmount &amount : CoinControlDialog::payAmounts)
     {
         nPayAmount += amount;
@@ -409,7 +408,6 @@ void CoinControlDialog::updateLabels(CCoinControl& m_coin_control, WalletModel *
         {
             // Assumes a p2pkh script size
             CTxOut txout(amount, CScript() << std::vector<unsigned char>(24, 0));
-            txDummy.vout.push_back(txout);
             fDust |= IsDust(txout, model->node().getDustRelayFee());
         }
     }

src/qt/transactionrecord.cpp

@@ -47,7 +47,6 @@ QList<TransactionRecord> TransactionRecord::decomposeTransaction(const interface
             if(mine)
             {
                 TransactionRecord sub(hash, nTime);
-                CTxDestination address;
                 sub.idx = i; // vout index
                 sub.credit = txout.nValue;
                 sub.involvesWatchAddress = mine & ISMINE_WATCH_ONLY;

src/wallet/wallet.cpp

@@ -746,7 +746,6 @@ void CWallet::SetSpentKeyState(WalletBatch& batch, const uint256& hash, unsigned
 bool CWallet::IsSpentKey(const uint256& hash, unsigned int n) const
 {
     AssertLockHeld(cs_wallet);
-    CTxDestination dst;
     const CWalletTx* srctx = GetWalletTx(hash);
     if (srctx) {
         assert(srctx->tx->vout.size() > n);