title: Composer exclude from class map won't work on absolute path with symlink
body: <p>I have the following autoload:</p>
  
  <pre><code>  "autoload" : {
      "classmap": ["src/", "../library/project/src", "tests/mocks"],
      "exclude-from-classmap": ["../psl-library/project/src/Couchbase.php"]
    }
  </code></pre>
  
  <p>The result is as I expected - inside autoload_classmap.php I get this:</p>
  
  <pre><code>'Couchbase' =&gt; $baseDir . '/tests/mocks/Couchbase.php'
  </code></pre>
  
  <p>I have made a symlink from to the <code>../library/project/src</code> to <code>/var/www/html/include/library</code></p>
  
  <p>Then my autoload looked like as follows:</p>
  
  <pre><code>  "autoload" : {
      "classmap": ["src/", "/var/www/html/include/library", "tests/mocks"],
      "exclude-from-classmap": ["/var/www/html/include/library/Couchbase.php"]
    }
  </code></pre>
  
  <p>When running autoload I get an unexpected result:</p>
  
  <pre><code>'Couchbase' =&gt; '/var/www/html/include/library/Couchbase.php'
  </code></pre>
  
  <p>Any idea  what might be the problem when working with absolute pathes or with symlinks?</p>