diff --git a/Include/compile.h b/Include/compile.h
index 4d0da38..5d65c5d 100644
--- a/Include/compile.h
+++ b/Include/compile.h
@@ -7,6 +7,9 @@
 extern "C" {
 #endif
 
+#define NESTED_SCOPES_DEFAULT 0
+#define FUTURE_NESTED_SCOPES "nested_scopes"
+
 /* Bytecode object */
 typedef struct {
     PyObject_HEAD
diff --git a/Include/symtable.h b/Include/symtable.h
index f96ed0c..eb0be1a 100644
--- a/Include/symtable.h
+++ b/Include/symtable.h
@@ -20,6 +20,7 @@
 
 struct symtable {
 	int st_pass;             /* pass == 1 or 2 */
+	int st_nested_scopes;    /* true if nested scopes are enabled */
 	char *st_filename;       /* name of file being compiled */
 	struct _symtable_entry *st_cur; /* current symbol table entry */
 	PyObject *st_symbols;    /* dictionary of symbol table entries */
@@ -40,7 +41,7 @@
 	PyObject *ste_children;  /* list of child ids */
 	int ste_type;            /* module, class, or function */
 	int ste_lineno;          /* first line of scope */
-	int ste_optimized;       /* true if namespace is optimized */
+	int ste_optimized;       /* true if namespace can't be optimized */
 	int ste_nested;          /* true if scope is nested */
 	int ste_child_free;      /* true if a child scope has free variables,
 				    including free refs to globals */
@@ -84,6 +85,10 @@
 #define FREE 4
 #define CELL 5
 
+#define OPT_IMPORT_STAR 1
+#define OPT_EXEC 2
+#define OPT_BARE_EXEC 4
+
 #ifdef __cplusplus
 }
 #endif