title: Install Go from source to custom prefix
body: <p>I have a Go installation in /usr, which is old (yum).  If I download the source from the Golang site and run the all.bash, the binaries and libraries are installed in the downloaded dir.</p>
  
  <p>With a usual Makefile, it's easy to set PREFIX, can this be done in the all.bash file somewhere?</p>