title: How do you build the 8g and 6g Go compilers for Go
body: <p>I'm writing software that will be somewhat widely deployed amongst Windows, Mac, and Linux systems on x86 and x86-64 architectures.  Whenever I set up the go compiler on my Mac and Linux systems I only ever get 6g built.  On Windows I just use the pre-built experimental binaries, which uses 8g.</p>
  
  <p>When I get around to setting up build servers, I assume I need to also build 8g so I can produce 32 bit builds as well.  How do I set up 8g, in particular on a Mac (since they can be x86 or x64 depending on how old they are)?</p>