exclude CreatePidFile() function on WIN32 as it is unused

src/bitcoind.cpp

@@ -74,7 +74,7 @@ bool AppInit(int argc, char* argv[])
             int ret = CommandLineRPC(argc, argv);
             exit(ret);
         }
-#if !defined(WIN32)
+#ifndef WIN32
         fDaemon = GetBoolArg("-daemon", false);
         if (fDaemon)
         {