Add compile flag to disable compilation of mining code

src/init.cpp

@@ -163,7 +163,9 @@ void Shutdown()
 #ifdef ENABLE_WALLET
     if (pwalletMain)
         pwalletMain->Flush(false);
+ #ifdef ENABLE_MINING
     GenerateBitcoins(false, NULL, 0);
+ #endif
 #endif
     StopNode();
     UnregisterNodeSignals(GetNodeSignals());
@@ -1500,7 +1502,7 @@ bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler)
                                          boost::ref(cs_main), boost::cref(pindexBestHeader), nPowTargetSpacing);
     scheduler.scheduleEvery(f, nPowTargetSpacing);
 
-#ifdef ENABLE_WALLET
+#if defined(ENABLE_WALLET) && defined(ENABLE_MINING)
     // Generate coins in the background
     if (pwalletMain)
         GenerateBitcoins(GetBoolArg("-gen", false), pwalletMain, GetArg("-genproclimit", 1));