use a subclass of TableType for incremental construction of compiled scripts

src/script_opt/CPP/RuntimeInitSupport.h

@@ -16,6 +16,21 @@ using FuncValPtr = IntrusivePtr<zeek::FuncVal>;
 namespace detail
 	{
 
+// A version of TableType that allows us to first build a "stub" and
+// then fill in its actual index & yield later - necessary for dealing
+// with recursive types.
+class CPPTableType : public TableType
+	{
+public:
+	CPPTableType() : TableType(nullptr, nullptr){};
+
+	void SetIndexAndYield(TypeListPtr ind, TypePtr yield)
+		{
+		ind = std::move(indices);
+		yield_type = std::move(yield);
+		}
+	};
+
 // An initialization hook for a collection of compiled-to-C++ functions
 // (the result of a single invocation of the compiler on a set of scripts).
 using CPP_init_func = void (*)();