Choices for <code>$GOOS</code> are <code>linux</code>,
<code>freebsd</code>,
<code>darwin</code> (Mac OS X 10.5 or 10.6),
- and <code>nacl</code> (Native Client, an incomplete port).
+ <code>nacl</code> (Native Client, an incomplete port),
+ and <code>windows</code> (Windows, an incomplete port).
Choices for <code>$GOARCH</code> are <code>amd64</code> (64-bit x86, the most mature port),
<code>386</code> (32-bit x86), and
<code>arm</code> (32-bit ARM, an incomplete port).