[XeTeX] caption problem with polyglossia

[François Charette]

>> 2- If we say, \setdefaultlanguage{farsi} and in the body have 
>> \section{فارسی}, at this stage, we get an error, but if we have 
>> \setdefaultlanguage{arabic} and then \setotherlanguage{farsi} and in 
>> the body we say
>> \begin{farsi}
>> \section{فارسی}
>> \end{farsi}
>> then the compile process is done without any errors.
>>     
> This is very strange!
>
>   
Fixed. I had forgotten to \protect things in the definition of 
\farsinumber :)