title: Issue building Linaro GDB for aarch64 on x86_64 host
body: <p>I downloaded the gdb sources from <a href="https://launchpad.net/gdb-linaro/" rel="nofollow noreferrer">https://launchpad.net/gdb-linaro/</a>.</p>
  
  <p>I want to build the gdb for aarch64.</p>
  
  <p>As mentioned in README file I set CC to the cross compiler that I have </p>
  
  <ol>
  <li>CC=aarch64-linux-gnu-gcc</li>
  <li>./configure --host=aarch64</li>
  </ol>
  
  <p>However this doesn't seem right as this sets the target to "aarch64-unknown-none"</p>
  
  <p>And later make fails as below
  *** BFD does not support target aarch64-unknown-none.</p>
  
  <p>I am not sure how to pass the correct target name required to cross compile gdb on my system.</p>
  
  <p>Any suggestions will help! :)</p>
  
  <p>Thanks,</p>
  
  <p>MS</p>