title: git diff between branches but ignoring the effect of certain commits
body: <p>We have 2 branches</p>
  
  <ul>
  <li>master</li>
  <li>branchX</li>
  </ul>
  
  <p>BranchX was created to solve some compatibility problem, where a about 10 files had to be changed.</p>
  
  <p>Development on master continues and at a certain stage, I want to check what will change when we merge master into branchX.</p>
  
  <p>What command should I use so that I can check that all merges have been done (except for the modifications on these 10 files)</p>