boost: drop boost threads for [alert|block|wallet]notify

src/wallet/wallet.cpp

@@ -34,7 +34,6 @@
 #include <future>
 
 #include <boost/algorithm/string/replace.hpp>
-#include <boost/thread.hpp>
 
 std::vector<CWalletRef> vpwallets;
 /** Transaction fee set by the user */
@@ -976,7 +975,8 @@ bool CWallet::AddToWallet(const CWalletTx& wtxIn, bool fFlushOnClose)
     if (!strCmd.empty())
     {
         boost::replace_all(strCmd, "%s", wtxIn.GetHash().GetHex());
-        boost::thread t(runCommand, strCmd); // thread runs free
+        std::thread t(runCommand, strCmd);
+        t.detach(); // thread runs free
     }
 
     return true;