diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
index 6c4225c..34ad6c3 100644
--- a/libcpp/include/cpplib.h
+++ b/libcpp/include/cpplib.h
@@ -437,6 +437,9 @@
   /* Nonzero for C++ 2014 Standard binary constants.  */
   unsigned char binary_constants;
 
+  /* Nonzero for C++ 2014 Standard digit separators.  */
+  unsigned char digit_separators;
+
   /* Holds the name of the target (execution) character set.  */
   const char *narrow_charset;