extensions: fix wrapcommand/function of class instance
5361771f9714 changed _updatewrapper() to copy the __name__ attribute, but
not all callable objects has __name__.
Spotted by loading mq with extdiff.
<Include>
<?if $(var.Platform) = "x64" ?>
<?define IsX64 = yes ?>
<?else?>
<?define IsX64 = no ?>
<?endif?>
</Include>