title: VK_KHR_WIN32_SURFACE_EXTENSION_NAME undefined, in Vulkan code
body: <p>I'm attempting to write a simple vulkan based application, but when trying to add the surface extension to the list of enabled extensions, like so:</p>
  
  <pre><code>    enabledExtensions.push_back( VK_KHR_SURFACE_EXTENSION_NAME );
  #if defined (_WIN32)
      enabledExtensions.push_back( VK_KHR_WIN32_SURFACE_EXTENSION_NAME );
  #else
      enabledExtensions.push_back( VK_KHR_XCB_SURFACE_EXTENSION_NAME );
  #endif
  </code></pre>
  
  <p>Visual studio complains that <code>VK_KHR_WIN32_SURFACE_EXTENSION_NAME</code>is undefined.</p>
  
  <p>When I right click it and go to definition, it opens vulkan.h. Upon inspection of <code>VK_USE_PLATFORM_WIN32_KHR</code> I find this to be also undefined, which prevents the definition of <code>VK_KHR_WIN32_SURFACE_EXTENSION_NAME</code>. Could someone explain how to fix this?</p>