title: What does the error "CPU you selected does not support x86-64 instruction set" mean?
body: <p>I installed <a href="http://pointclouds.org/" rel="nofollow">Point Cloud Library</a> from the ppa for in Ubuntu 11.10 x86_64 (including the dev packages, not necessarily relevant for the question but for the sake of completeness I am providing this detail).
  When I am trying to compile (make on a cmake generated make file) my own code which uses pcl I am getting the error <strong>CPU you selected does not support x86-64 instruction set</strong>. 
  What does this error mean and what all should I check in order to remove the error?</p>