Proposed doc update for Explicit Reg Vars 2/3

[Jeff Law]

On 10/21/2015 05:27 AM, Segher Boessenkool wrote:
> On Tue, Oct 20, 2015 at 09:24:48PM -0700, David Wohlferd wrote:
>>>> +Registers can be a limited resource on some systems and allowing the
>>> They are a limited resource on almost all systems.  "Scarce resource"?
>>
>> "Scarce" it is.  I've left the rest alone for the moment, but how would
>> you feel about:
>>
>> "Registers are a scarce resource on most systems and allowing the"
>
> That sounds fine.
I installed this patch from David with an update to use the "Registers 
are a scarce resource ..." text.

Thanks David & Segher.

jeff