diff --git a/xwords4/relay/cref.cpp b/xwords4/relay/cref.cpp
index 3062fd23c..1214d5cac 100644
--- a/xwords4/relay/cref.cpp
+++ b/xwords4/relay/cref.cpp
@@ -24,6 +24,7 @@
 #include <pthread.h>
 #include <netinet/in.h>
 #include <stdarg.h>
+#include <stdio.h>
 
 #include "cref.h"
 #include "xwrelay.h"
@@ -798,7 +799,7 @@ CookieRef::logf( XW_LogLevel level, const char* format, ... )
     char buf[256];
     int len;
 
-    len = snprintf( buf, sizeof(buf), "cid:%d ", m_cookieID );
+      len = snprintf( buf, sizeof(buf), "cid:%d ", m_cookieID );
 
     va_list ap;
     va_start( ap, format );
diff --git a/xwords4/relay/crefmgr.cpp b/xwords4/relay/crefmgr.cpp
index 0b9f2f12c..b84ba03f9 100644
--- a/xwords4/relay/crefmgr.cpp
+++ b/xwords4/relay/crefmgr.cpp
@@ -19,6 +19,7 @@
  */
 
 #include <assert.h>
+#include <stdio.h>
 #include <pthread.h>
 
 #include "crefmgr.h"
diff --git a/xwords4/relay/tpool.cpp b/xwords4/relay/tpool.cpp
index 20a277094..00b46a282 100644
--- a/xwords4/relay/tpool.cpp
+++ b/xwords4/relay/tpool.cpp
@@ -19,6 +19,7 @@
  */
 
 #include <assert.h>
+#include <stdio.h>
 #include <unistd.h>
 #include <pthread.h>
 #include <sys/types.h>