diff --git a/xwords4/linux/Makefile b/xwords4/linux/Makefile
index 7d0291762..4e3ee8ffe 100644
--- a/xwords4/linux/Makefile
+++ b/xwords4/linux/Makefile
@@ -122,7 +122,7 @@ endif
 # DEFINES += -DXWFEATURE_IR
 DEFINES += ${BLUETOOTH}
 DEFINES += -DXWFEATURE_RELAY
-DEFINES += -DXWFEATURE_SMS
+DEFINES += -DXWFEATURE_SMS -DXWFEATURE_BASE64
 
 # Robot can be made to think, to simulate for relay mostly
 DEFINES += -DXWFEATURE_SLOW_ROBOT