If on w32 default-directory is something like c:\top\sub then the
subprocess started by compilation-start will get pwd=c:\top.

This can be cured by the attached patch for this special case, but it is
only a demonstration of the problem, not the right fix for this problem.

The attached patch only does

  (let ((default-directory (file-name-as-directory default-directory))

just before calling `start-file-process-shell-command'.

A slightly better fix would probably be to add the same thing in
`start-file-process', but it seems to me that this should handled at the
C level to catch all cases. I do not know where to do that but it must
be done somewhere before make_process in start-process.


In GNU Emacs 23.0.60.1 (i386-mingw-nt5.1.2600)
 of 2008-08-10
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (3.4) --no-opt --cflags
-Ic:/g/include -fno-crossjumping'