[cairo] strndup

[John Emmas]

I'm building cairo with MSVC.  I just updated from git master and 
noticed that some new source files got added, including 
'cairo-pdf-interchange.c'.  It contains a function called split_label() 
which returns like this:-

     if (i > 0)
        return strndup (label, i);

     return NULL;

AFAICT, MSVC doesn't seem to offer 'strndup()'.  Could something else be 
used instead?  Thanks,

John