title: Remove trailing newline from esyscmd in m4
body: <p>I'm using m4 to create some basic macros and I realize that when using <code>esyscmd</code> there's a trailing new line added to a string when the command is run.</p>
  
  <p>Example:</p>
  
  <pre><code>define(MY_HOSTNAME, esyscmd(`hostname'))
  MY_HOSTNAME
  Some other text...
  </code></pre>
  
  <p>Renders:</p>
  
  <pre><code>&gt; my.host.name
  &gt;
  &gt; Some other text...
  </code></pre>
  
  <p>(complete with a trailing new line)</p>
  
  <p>By adding <code>dnl</code> at the end of the define (or esyscmd) nothing appears to happen and there's still a trailing newline.</p>
  
  <p>What's the best way to drop the trailing newline when calling <code>esyscmd</code> in m4?</p>