Fix LaTeX export when there is no #+TEXT stuff

lisp/org-latex.el

@@ -640,22 +640,23 @@ when PUB-DIR is set, use this as the publishing directory."
 		  (if region-p (region-beginning) (point-min))
 		  (if region-p (region-end) (point-max))))
 	 (text
-	  (org-export-preprocess-string
-	   text
-	   :emph-multiline t
-	   :for-LaTeX t
-	   :comments nil
-	   :tags (plist-get opt-plist :tags)
-	   :priority (plist-get opt-plist :priority)
-	   :footnotes (plist-get opt-plist :footnotes)
-	   :drawers (plist-get opt-plist :drawers)
-	   :timestamps (plist-get opt-plist :timestamps)
-	   :todo-keywords (plist-get opt-plist :todo-keywords)
-	   :add-text nil
-	   :skip-before-1st-heading skip
-	   :select-tags nil
-	   :exclude-tags nil
-	   :LaTeX-fragments nil))
+	  (and text (string-match "\\S-" text)
+	       (org-export-preprocess-string
+		text
+		:emph-multiline t
+		:for-LaTeX t
+		:comments nil
+		:tags (plist-get opt-plist :tags)
+		:priority (plist-get opt-plist :priority)
+		:footnotes (plist-get opt-plist :footnotes)
+		:drawers (plist-get opt-plist :drawers)
+		:timestamps (plist-get opt-plist :timestamps)
+		:todo-keywords (plist-get opt-plist :todo-keywords)
+		:add-text nil
+		:skip-before-1st-heading skip
+		:select-tags nil
+		:exclude-tags nil
+		:LaTeX-fragments nil)))
 	 (string-for-export
 	  (org-export-preprocess-string
 	   region