fix SETUPFILE pathname expansion with subdirectories

* lisp/org-macro.el (org-macro--collect-macros): cd to the directory
containing the SETUPFILE before recursing so that relative pathnames
in the SETUPFILE are expanded properly.

* lisp/org.el (org--setup-collect-keywords): cd to the directory
containing the SETUPFILE before recursing so that relative pathnames
in the SETUPFILE are expanded properly.

* lisp/ox.el (org-export--get-inbuffer-options,
org-export--list-bound-variables): cd to the directory containing the
SETUPFILE before recursing so that relative pathnames in the SETUPFILE
are expanded properly.

If /path/to/foo.org contains:

    #+SETUPFILE: settings/beamer.org

and /path/to/settings/beamer.org contains:

    #+SETUPFILE: common.org

then we want to read /path/to/settings/common.org, not
/path/to/common.org.

TINYCHANGE

lisp/org-macro.el

@@ -106,6 +106,8 @@ Return an alist containing all macro templates found."
 				      (org-remove-double-quotes val))))
 			   (unless (member file files)
 			     (with-temp-buffer
+			       (setq default-directory
+				     (file-name-directory file))
 			       (org-mode)
 			       (insert (org-file-contents file 'noerror))
 			       (setq templates

lisp/org.el

@@ -5208,6 +5208,7 @@ Return value contains the following keys: `archive', `category',
 				(org-remove-double-quotes value)))))
 		   (when (and f (file-readable-p f) (not (member f files)))
 		     (with-temp-buffer
+		       (setq default-directory (file-name-directory f))
 		       (insert-file-contents f)
 		       (setq alist
 			     ;; Fake Org mode to benefit from cache

lisp/ox.el

@@ -1455,6 +1455,8 @@ Assume buffer is in Org mode.  Narrowing, if any, is ignored."
 			 ;; Avoid circular dependencies.
 			 (unless (member file files)
 			   (with-temp-buffer
+			     (setq default-directory
+				   (file-name-directory file))
 			     (insert (org-file-contents file 'noerror))
 			     (let ((org-inhibit-startup t)) (org-mode))
 			     (setq plist (funcall get-options
@@ -1586,6 +1588,8 @@ an alist where associations are (VARIABLE-NAME VALUE)."
 					(org-remove-double-quotes val))))
 			     (unless (member file files)
 			       (with-temp-buffer
+				 (setq default-directory
+				       (file-name-directory file))
 				 (let ((org-inhibit-startup t)) (org-mode))
 				 (insert (org-file-contents file 'noerror))
 				 (setq alist

testing/examples/setupfile.org

@@ -1,6 +1 @@
-#+BIND: variable value
-#+DESCRIPTION: l2
-#+LANGUAGE: en
-#+SELECT_TAGS: b
-#+TITLE: b
-#+PROPERTY: a 1
+#+SETUPFILE: subdir/setupfile2.org

testing/examples/setupfile3.org

@@ -0,0 +1,6 @@
+#+BIND: variable value
+#+DESCRIPTION: l2
+#+LANGUAGE: en
+#+SELECT_TAGS: b
+#+TITLE: b
+#+PROPERTY: a 1

testing/examples/subdir/setupfile2.org

@@ -0,0 +1 @@
+#+SETUPFILE: ../setupfile3.org