title: How to rebuild all library after upgrading Go 1.4
body: <p>I was using Go 1.3.3. After installing 1.4, there are many errors similar to this:</p>
  
  <pre><code>db/base.go:4: import /home/asd/Dropbox/go/pkg/linux_amd64/projc1/libs/Bool.a: 
   object is [linux amd64 go1.3.3 X:precisestack] 
    expected [linux amd64 go1.4 X:precisestack]
  </code></pre>
  
  <p>How do I resolve this? I've tried <code>go build</code> on <code>$GOPATH/src/projc1/libs/Bool/</code> but it has no effect.</p>