Initial check in of icontext.

include/decl.h

@@ -439,8 +439,20 @@ struct early_opt {
     boolean valallowed;
 };
 
-/* encumbrance */
-E int oldcap;
+/* instance_context holds per game instance data that does not need to be
+ * persisted upon game exit.  This game instance data is one of the first
+ * things initialized during the initialization of the game engine.
+ * It is initialized with icontext_initial_state found in decl.c */
+
+#define PLAYAGAIN
+
+struct instance_context {
+    int oldcap; /* encumberance - pickup.c */
+};
+
+E struct instance_context icontext;
+
+E void icontext_init();
 
 
 #undef E