compilation-last-buffer and compilation-minor-mode

[Stefan Monnier <monnier@iro.umontreal.ca>]

In Emacs-21, calling compilation-minor-mode used to set
compilation-last-buffer to the current-buffer.  In Emacs-CVS this is not the
case any more.  The change that causes this is:

2004-04-21  Teodor Zlatanov  <tzz@lifelogs.com>

	* simple.el (next-error-last-buffer, next-error-function):
	New variables for the next-error framework.
	(next-error-buffer-p): New function.
	(next-error-find-buffer): Generalize compilation-find-buffer.
	(next-error, previous-error, first-error, next-error-no-select)
	(previous-error-no-select): Move from compile.el.

	* replace.el (occur-next-error, occur-1): Hook into the next-error
	framework.

	* progmodes/compile.el (compilation-start):
	Set next-error-last-buffer so next-error knows where to jump.
	(compilation-setup): Set the buffer-local variable
	next-error-function to 'compilation-next-error-function.
	(compilation-buffer-p, compilation-buffer-internal-p): Use an
	alternate way to find if a buffer is a compilation buffer, for
	next-error convenience.
	(next-error-no-select, previous-error-no-select, next-error)
	(previous-error, first-error): Move to simple.el.
	(compilation-find-buffer): Move to next-error-find-buffer in simple.el.
	(compilation-last-buffer): Remove.
	(compilation-start, compilation-next-error, compilation-setup)
	(compilation-next-error-function, compilation-find-buffer):
	Remove compilation-last-buffer use.

The problem with this change is that for packages which use an inferior
(comint) interactive process to do the compilation (such as sml-mode,
haskell-mode, etc...), C-x ` doesn't work from the source buffer any more
(at least not until you used it from the comint buffer).

Now, the only place where compilation-last-buffer (aka
next-error-last-buffer) is set is in `compilation-start', which can't be
used for those cases.

So should we revert this part of the above change, or should sml-mode and
haskell-mode just manually set next-error-last-buffer, or should we introduce
a function that they can call?


        Stefan