atomic support for LEON3 platform

[Eric Botcazou]

> Hi Eric, do you mean that you already have a patch to solve this issue
> which is just not merged to mainline? If yes could you send me your patch
> and tell me to how enable this feature? Thank you!

No, I only installed a patch on the trunk that adds the basic infrastructure 
for a LEON3 variant of the compiler (we only had a LEON variant before).  The 
underlying architecture is still a strict V8 so it won't generate 'cas', but it 
will not be difficult to instruct it to do so once binutils support is there.

-- 
Eric Botcazou