Default compute dimensions

[Nathan Sidwell]

On 02/01/16 13:42, Jakub Jelinek wrote:

> Your patch broke bootstrap on ILP32 hosts, I'm testing following fix.
> Supporting unsigned values from 0x80000000U to 0xffffffffU only on LP64
> hosts and not on ILP64 hosts sounds really weird, I think it is better
> to only support 1 to 0x7fffffffU.

yes, I must have missed that first cast when changing my mind over 
signed/unsigned.  thanks!

nathan