Add command-line -enable-cdef option

Change-Id: Ic061eeab1563c249fd9d3738025aac40bc3ee542
diff --git a/av1/encoder/encoder.h b/av1/encoder/encoder.h
index 32cb2f1..3584098 100644
--- a/av1/encoder/encoder.h
+++ b/av1/encoder/encoder.h
@@ -196,6 +196,9 @@
 #if CONFIG_EXT_DELTA_Q
   DELTAQ_MODE deltaq_mode;
 #endif
+#if CONFIG_CDEF
+  int using_cdef;
+#endif
 #if CONFIG_AOM_QM
   int using_qm;
   int qm_minlevel;