title: Specify the gcc version for bitbake meta-toolchain
body: <p>I'm just starting to learn Yocto 1.8.</p>
  
  <p>The <code>bitbake meta-toolchain</code> ran fine as described in the documentation and generated the appropriate installation script. However, <code>bitbake</code> picked a version of GCC that I don't want.
  What is the recommended way to tell <code>bitbake</code> which version of GCC to pick for the <code>bitbake meta-toolchain</code> build?</p>