title: Warning when compiling .cu with -Wpedantic: "style of line directive is a GCC extension"
body: <p>I'm collaborating on an opensource project where the global compiler settings include <code>-Werror</code> and <code>-pedantic</code>, so in order to have my contributions accepted, I'll have to comply with those.</p>
  <p>Second, I'm a Windows person, so I have happily built a new component of this project, only to realize now that it doesn't compile on Linux, throwing the following warning:</p>
  <pre><code>style of line directive is a GCC extension
  </code></pre>
  <p>on every single line (on every 3rd char to be specific) of a CUDA (.cu) source file that is part of my component.</p>
  <p>I'm using cmake with the <code>FindCUDA.cmake</code> scripts to compile CUDA. The source file doesn't contain any <code>#line</code> directive so I'm completely clueless as to what GCC is complaining about.</p>
  <p>First I thought it was line-endings, but the Linux &quot;file&quot; command reports the <code>.cu</code> file as &quot;C source, ASCII text&quot;, no &quot;with CRLF line terminators&quot;.</p>
  <p>The rest of the opensource project doesn't contain any CUDA, so I have nothing to compare with.</p>
  <p>What does this warning mean exactly, and how do I get rid of it?</p>