guard-clause use of syslog object

src/RedirectablePrint.cpp

@@ -13,7 +13,9 @@
  */
 NoopPrint noopPrint;
 
+#if HAS_WIFI || HAS_ETHERNET
 extern Syslog syslog;
+#endif
 
 void RedirectablePrint::setDestination(Print *_dest)
 {
@@ -99,6 +101,7 @@ size_t RedirectablePrint::log(const char *logLevel, const char *format, ...)
         }
         r += vprintf(format, arg);
 
+#if HAS_WIFI || HAS_ETHERNET
         // if syslog is in use, collect the log messages and send them to syslog
         if (syslog.isEnabled()) {
             int ll = 0;
@@ -123,6 +126,7 @@ size_t RedirectablePrint::log(const char *logLevel, const char *format, ...)
             }
             syslog.vlogf(ll, format, arg);
         }
+#endif
 
         va_end(arg);