Revert "rename amd64 architecture to x86_64" This reverts commit c1543a890188d397acca9fe7f76bcd982481a763. I'm reverting it because: 1) the change didn't get properly discussed 2) it was based on false premises: "The rest of the world seems to call amd64 x86_64." 3) no pkgsrc bulk build was done to test the change 4) the original committer acted irresponsibly by committing such a big change just before going on vacation.