gdb-ui doesn't work with comint read-only prompts

[Nick Roberts]

 > Customize the comint prompts to be read-only (in customize group
 > "comint"), then try starting a gdb session and typing some commands.
 > 
 > You get various "text is read-only" errors, and things generally don't
 > work right.

You get the same errors with "gdb -fullname" if you execute commands using the
toolbar or keybindings e.g C-x C-a C-n.  That's because GUD deletes the
existing prompt in this and replaces it with the new one.  The variable
comint-prompt-read-only is quite new.  Why would someone set it to t?

Nick