title: vim clang complete doesn't see some functions of opengl
body: <p>I have <code>vim</code> and <code>clang_complete</code> installed but for some reason when I try to auto complete it doesn't see some of OpenGL's functions, such as <code>glBindBuffer</code>, or <code>glEnableVertexAttribArray</code>. I press <kbd>CTRL</kbd> + <kbd>X</kbd> and <kbd>CTRL</kbd> + <kbd>U</kbd> to force the auto complete and it shows the function names and parameters, but it's just missing some of the functions.</p>
  
  <p>Even with <code>glfw</code>, I try auto completing <code>GLFW_KEY_ESC</code> but it's not there, I don't know why, it just says <code>User defined completion (^U^N^P) Pattern not found</code></p>
  
  <p>Does anyone have a solution to this problem? It's very annoying because I use these functions a lot and need the auto complete.</p>
  
  <p>Thanks.</p>
  
  <p>EDIT: Also my include header files are this:</p>
  
  <pre><code>#include &lt;iostream&gt;
  #include &lt;string&gt;
  #include &lt;GL/glew.h&gt;
  #include &lt;GL/glfw.h&gt;
  #include &lt;glm/glm.hpp&gt;
  </code></pre>
  
  <p>I'm on <code>Arch Linux x64</code> by the way.</p>