+/* Lisp fields in struct keyboard are hidden from most code and accessed
+ via the KVAR macro, below. Only select pieces of code, like the GC,
+ are allowed to use KBOARD_INTERNAL_FIELD. */
+#define KBOARD_INTERNAL_FIELD(field) field ## _
+
+/* Most code should use this macro to access Lisp fields in struct
+ kboard. */
+#define KVAR(kboard, field) ((kboard)->KBOARD_INTERNAL_FIELD (field))