Remove unused MakeOptional

The only use was to work around a compiler warning in an ancient
compiler, which we no longer support.

src/optional.h

@@ -13,13 +13,6 @@
 template <typename T>
 using Optional = boost::optional<T>;
 
-//! Substitute for C++17 std::make_optional
-template <typename T>
-Optional<T> MakeOptional(bool condition, T&& value)
-{
-    return boost::make_optional(condition, std::forward<T>(value));
-}
-
 //! Substitute for C++17 std::nullopt
 static auto& nullopt = boost::none;
 

src/wallet/rpcwallet.cpp

@@ -1573,8 +1573,7 @@ static RPCHelpMan listsinceblock()
 
     LOCK(wallet.cs_wallet);
 
-    // The way the 'height' is initialized is just a workaround for the gcc bug #47679 since version 4.6.0.
+    Optional<int> height;    // Height of the specified block or the common ancestor, if the block provided was in a deactivated chain.
-    Optional<int> height = MakeOptional(false, int()); // Height of the specified block or the common ancestor, if the block provided was in a deactivated chain.
     Optional<int> altheight; // Height of the specified block, even if it's in a deactivated chain.
     int target_confirms = 1;
     isminefilter filter = ISMINE_SPENDABLE;
@@ -3597,7 +3596,7 @@ static RPCHelpMan rescanblockchain()
     }
 
     int start_height = 0;
-    Optional<int> stop_height = MakeOptional(false, int());
+    Optional<int> stop_height;
     uint256 start_block;
     {
         LOCK(pwallet->cs_wallet);

src/wallet/wallet.cpp

@@ -4055,8 +4055,7 @@ std::shared_ptr<CWallet> CWallet::Create(interfaces::Chain& chain, const std::st
 
         // No need to read and scan block if block was created before
         // our wallet birthday (as adjusted for block time variability)
-        // The way the 'time_first_key' is initialized is just a workaround for the gcc bug #47679 since version 4.6.0.
+        Optional<int64_t> time_first_key;
-        Optional<int64_t> time_first_key = MakeOptional(false, int64_t());;
         for (auto spk_man : walletInstance->GetAllScriptPubKeyMans()) {
             int64_t time = spk_man->GetTimeFirstKey();
             if (!time_first_key || time < *time_first_key) time_first_key = time;