Fix bug #16099 with failed out-of-tree builds on MS-Windows.

 lisp/Makefile.in (autoloads): Run $(srcdir)/loaddefs.el through
 unmsys--file-name.

lisp/ChangeLog

+2013-12-10  Eli Zaretskii  <eliz@gnu.org>
+
+	* Makefile.in (autoloads): Run $(srcdir)/loaddefs.el through
+	unmsys--file-name.  (Bug#16099)
+
 2013-12-10  Teodor Zlatanov  <tzz@lifelogs.com>
 
 	* emacs-lisp/package.el (package-keyword-button-action): Remove

lisp/Makefile.in

@@ -183,7 +183,7 @@ autoloads: $(LOADDEFS) doit
 	echo Directories: $$wins; \
 	$(emacs) -l autoload \
 	    --eval '(setq autoload-builtin-package-versions t)' \
-	    --eval '(setq generated-autoload-file (expand-file-name "$(srcdir)/loaddefs.el"))' \
+	    --eval '(setq generated-autoload-file (expand-file-name (unmsys--file-name "$(srcdir)/loaddefs.el")))' \
 	    -f batch-update-autoloads $$wins
 
 # This is required by the bootstrap-emacs target in ../src/Makefile, so