base|krb5: struct krb5_config_binding is public

ea90ca8666
("Move some infra bits of lib/krb5/ to lib/base/ (2)") introduced
struct heim_config_binding to heimbase.h and removed the
struct krb5_config_binding definition from krb5.h.  It changed
the krb5_config_binding typedef to be based upon the heim_config_binding
typedef.

These changes broke out of tree callers of krb5_config_get_list()
and krb5_config_vget_list().  The internals of struct krb5_config_binding
are required by callers of krb5_config_get_list() and krb5_config_vget_list()
and the names must remain the same.

This change restores struct krb5_config_binding to krb5.h.  The
structure cannot be changed because it is public and leaves struct
heim_config_binding as an independent structure definition within
heimbase.h.  As a result struct heim_config_binding in heimbase.h must
remain binary compatible until such time as krb5_config_get_list() and
krb5_config_vget_list() are no longer supported.

Change-Id: I69b4fda3f656cc8daa8f5fcd0c7151cee222fc8c

lib/base/heimbase.h

@@ -120,15 +120,17 @@ struct heim_plugin_data {
     heim_get_instance_func_t get_instance;
 };
 
-typedef struct heim_config_binding heim_config_binding;
+/*
+ * heim_config_binding is identical to struct krb5_config_binding
+ * within krb5.h.  Its format is public and used by callers of
+ * krb5_config_get_list() and krb5_config_vget_list().
+ */
+enum heim_config_type {
+    heim_config_string,
+    heim_config_list,
+};
 struct heim_config_binding {
-    enum {
-        heim_config_string,
-        heim_config_list,
-        /* For compatibility in krb5 code */
-        krb5_config_string = heim_config_string,
-        krb5_config_list = heim_config_list,
-    } type;
+    enum heim_config_type type;
     char *name;
     struct heim_config_binding *next;
     union {
@@ -137,6 +139,7 @@ struct heim_config_binding {
         void *generic;
     } u;
 };
+typedef struct heim_config_binding heim_config_binding;
 typedef struct heim_config_binding heim_config_section;
 
 /*