Finding the machine CPU arch

[Ryan Schmidt]

On Mar 6, 2013, at 08:52, Joshua Root wrote:
> On 2013-3-7 00:29 , Vincent Habchi wrote:
>> is there a variable that gives the type of the processor Macports is running on? ${os.arch} does not discriminate between i386 and x86_64. Anything more precise?
> 
> Well, build_arch tells you what kind of processor the user wants you to
> build for. In general you can't assume that the CPU you're building on
> is the one that you will run on.

Atlas seems to be one of those performance-critical ports that could benefit by being compiled for the user's specific processor instead of using a pre-compiled binary that might have been build for a slightly different processor. To that end, Vincent is going to be clearing archive_sites in the next update to the atlas port. Users could still manually transport an archive from one machine to another and thereby possibly get suboptimal performance, but I think we're assuming users won't do that.