#9907: call rl_initialize early when using editline on OSX

editline rl_initialize apparently discards any mappings done before it
is called, which makes tab revert to file completion instead of inserting
a tab.  So now on OSX we call rl_initialize first if we are using
readline, and then re-read the users .editrc (if any) afterward so they
can still override our defaults.

Patch by Ned Deily, modified by Ronald Oussoren.

Misc/NEWS

@@ -20,6 +20,9 @@ Core and Builtins
 Library
 -------
 
+- Issue $9907: Fix tab handling on OSX when using editline by calling
+  rl_initialize first, then setting our custom defaults, then reading .editrc.
+
 - Issue #4188: Avoid creating dummy thread objects when logging operations
   from the threading module (with the internal verbose flag activated).
 

Modules/readline.c

@@ -889,6 +889,14 @@ setup_readline(void)
         Py_FatalError("not enough memory to save locale");
 #endif
 
+#ifdef __APPLE__
+    /* the libedit readline emulation resets key bindings etc 
+     * when calling rl_initialize.  So call it upfront
+     */
+    if (using_libedit_emulation)
+        rl_initialize();
+#endif /* __APPLE__ */
+
     using_history();
 
     rl_readline_name = "python";
@@ -920,8 +928,13 @@ setup_readline(void)
      * XXX: A bug in the readline-2.2 library causes a memory leak
      * inside this function.  Nothing we can do about it.
      */
-    rl_initialize();
-
+#ifdef __APPLE__
+    if (using_libedit_emulation)
+	rl_read_init_file(NULL);
+    else
+#endif /* __APPLE__ */
+        rl_initialize();
+    
     RESTORE_LOCALE(saved_locale)
 }