Fix LaTeX and Beamer publishing processes

* lisp/ox-beamer.el (org-beamer-publish-to-pdf):
* lisp/ox-latex.el (org-latex-publish-to-pdf): Set default directory
  prior to compiling the generated tex file.

Reported-by: Robert Klein <roklein@roklein.de>
<http://permalink.gmane.org/gmane.emacs.orgmode/112388>

lisp/ox-beamer.el

@@ -1122,9 +1122,13 @@ Return output file name."
   ;; working directory and then moved to publishing directory.
   (org-publish-attachment
    plist
-   (org-latex-compile
-    (org-publish-org-to
-     'beamer filename ".tex" plist (file-name-directory filename)))
+   ;; Default directory could be anywhere when this function is
+   ;; called.  We ensure it is set to source file directory during
+   ;; compilation so as to not break links to external documents.
+   (let ((default-directory (file-name-directory filename)))
+     (org-latex-compile
+      (org-publish-org-to
+       'beamer filename ".tex" plist (file-name-directory filename))))
    pub-dir))
 
 

lisp/ox-latex.el

@@ -3692,9 +3692,13 @@ Return output file name."
   ;; in working directory and then moved to publishing directory.
   (org-publish-attachment
    plist
-   (org-latex-compile
-    (org-publish-org-to
-     'latex filename ".tex" plist (file-name-directory filename)))
+   ;; Default directory could be anywhere when this function is
+   ;; called.  We ensure it is set to source file directory during
+   ;; compilation so as to not break links to external documents.
+   (let ((default-directory (file-name-directory filename)))
+     (org-latex-compile
+      (org-publish-org-to
+       'latex filename ".tex" plist (file-name-directory filename))))
    pub-dir))