Use \providecommand to make sure \alert is defined

lisp/ChangeLog

@@ -1,5 +1,8 @@
 2010-02-03  Carsten Dominik  <carsten.dominik@gmail.com>
 
+	* org-latex.el (org-export-latex-make-header): Use \providecommand
+	to make sure the \alert macro is defined.
+
 	* org.el (org-format-latex-signal-error)
 	(org-create-formula-image): Use `org-format-latex-signal-error'.
 

lisp/org-latex.el

@@ -1147,7 +1147,7 @@ OPT-PLIST is the options plist for current buffer."
       (plist-get opt-plist :latex-header-extra))
      (org-export-apply-macros-in-string org-export-latex-append-header)
      ;; define align if not yet defined
-     "\\ifx\\alert\\undefined\\let\\alert\\textbf\\fi"
+     "\\providecommand{\\alert}[1]{\\textbf{#1}}"
      ;; insert the title
      (format
       "\n\n\\title{%s}\n"