Patch for IA64 32-bit function descriptors

[Benjamin Kosnik]

> > I'm not sure why target-specific padding is being added to this
> > struct.
> 
> Because several someones at HP were idiots.

[snip]

Apparently so. Thanks.

> > Isn't there a better way of doing this than hacking up common code
> > for IA64 and HPUX issues?
> 
> *shrug* Probably not.

This is the only target-specific code in this file. It seems like a bad
idea to start doing this. Perhaps HP could live with this as a local
hack in their tree?

-benjamin