** Create a category of errors called `process-error'
for some or all errors associated with using subprocesses.
+** Maybe reinterpret `parse-error' as a category of errors
+ and put some other errors under it.
+
** A function to check for customizable options that have been
set but not saved, and ask the user whether to save them.
This could go in kill-emacs-query-functions, to remind people