[LLVMdev] avoid creating .dir files

[Mike Stump]

On Jan 20, 2009, at 12:46 PM, Dan Villiom Podlaski Christiansen wrote:
> One way to solve this is by using an order-only dependancy:

Cool.  That's a good solution, with this, we can avoid the mkdir as  
well.

> Is it possible that I could get you to wait a bit with these changes?

No time like the present.  I've used that incantation, feel free to  
suggest/make improvements.  Also, I only did this for the installation  
directories, as those were the critical ones.