Remove false positive GCC warning

Author: hebasto

src/wallet/wallet.cpp

@@ -13,6 +13,7 @@
 #include <interfaces/wallet.h>
 #include <key.h>
 #include <key_io.h>
+#include <optional.h>
 #include <policy/fees.h>
 #include <policy/policy.h>
 #include <primitives/block.h>
@@ -3910,7 +3911,8 @@ std::shared_ptr<CWallet> CWallet::CreateWalletFromFile(interfaces::Chain& chain,
 
         // No need to read and scan block if block was created before
         // our wallet birthday (as adjusted for block time variability)
-        Optional<int64_t> time_first_key;
+        // 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 = 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;