enum ir_variable_mode mode);
/*@}*/
+ /**
+ * Disable a previously-added variable so that it no longer appears to be
+ * in the symbol table. This is necessary when gl_PerVertex is redeclared,
+ * to ensure that previously-available built-in variables are no longer
+ * available.
+ */
+ void disable_variable(const char *name);
+
private:
symbol_table_entry *get_entry(const char *name);