New "external command" command in mcedit (latest CVS version)

[Roland Illig]

Hi,

I have replaced the "external command" in mcedit with my own version 
which I find much nicer. It has some new features over the old one:

- It feeds the currently selected block to the external command,
   if one is selected.
- If the command exits with a nonzero status, the user is asked
   whether {s,}he wants to insert the output anyway. Useful for
   diff(1) which returns 1 if the files differ.
- Because it always feeds an input stream to the command, you can
   now safely execute "cat" without hanging mcedit (which had been
   the case before).

The downside of the new version:

- It uses brand new code (less than a week old) which I have only
   tried under Linux (and you know that Linux tries to accept all
   programming errors instead of returning error values). So I
   expect that the code might fail on some other systems.

Please try if it works on your favourite system and tell me about it.

Roland