bug#21162: adapting octave-inf.el to Octave 4

[Francesco Potortì]

>> The following patch does two things:
>>
>> 1) it removes the --no-line-editing option when calling the Octave
>>    process, for reasons that I explained in my previous bug report about
>>    octave-inf.el
>>
>> 2) it adds the --no-gui option when calling Octave if its version is
>>    different from 3: this is needed because the last (and future,
>>    probably) Octave versions launch a GUI by default
>
>There is no file "octave-inf.el" in Emacs for some time,
>and "inferior-octave-startup" has contained code to call "--no-gui" for
>the past two years, so please review the situation in current Emacs
>master and send a revised patch, if one is still needed. Thanks.

Sorry, I live behind the times :)

With the newest version, it's easier: just remove the --no-line-editing
option from the initialization of inferior-octave-startup-args:

--- octave.el.old       2015-07-31 11:19:50.203406678 +0200
+++ octave.el.new       2015-07-31 11:19:55.647504953 +0200
@@ -641,7 +641,7 @@
   :group 'octave
   :version "24.4")
 
-(defcustom inferior-octave-startup-args '("-i" "--no-line-editing")
+(defcustom inferior-octave-startup-args '("-i")
   "List of command line arguments for the inferior Octave process.
 For example, for suppressing the startup message and using `traditional'
 mode, include \"-q\" and \"--traditional\"."


Reason for changelog entry:

--no-line-editing serves no apparent purpose (any more?) and prevents an
inferior Octave process from using readline features, like getting the
terminal width and other functions used for the FLTK graphical backend.

Thanks