Merge pull request #3883 from dgenr8/first_double_spend

Relay and alert user to double spends

src/main.h

@@ -108,6 +108,9 @@ struct CNodeStateStats;
 
 struct CBlockTemplate;
 
+/** Set up internal signal handlers **/
+void RegisterInternalSignals();
+
 /** Register a wallet to receive updates from core */
 void RegisterWallet(CWalletInterface* pwalletIn);
 /** Unregister a wallet from core */