title: Build tensorflow faster from source for contribution purposes
body: <p>I am building <code>tensorflow</code> with <code>bazel</code> on my local PC, but as expected it takes quite a long time. The problem is that I want to make my own contributions in the source, so it's not feasible to compile all over again the whole code for every small change that I am making. I want to use tensorflow for a custom project of mine, thus I cannot rely/expect on/from the community to take any issues of mine into consideration.</p>
  <ol>
  <li>Are there certain targets I may could use with <code>bazel</code>, just like if I was using <code>make</code>?</li>
  <li>I have access to a pretty good GPU server but I cannot figure out whether <code>tensorflow-bazel</code> uses GPU resources for building. Are there any configurations I could use for building with GPU?</li>
  <li>What's the fastest way to re-compile <code>tensorflow</code>  in general all over again, for every small tweak that I am applying?</li>
  </ol>
  <p>How do independent contributors work on <code>tensorflow</code> in general?</p>