cxx: Use pragma once consistently for non-api headers

include/vulkan/vk_icd.h

@@ -19,9 +19,7 @@
  * limitations under the License.
  *
  */
-
-#ifndef VKICD_H
-#define VKICD_H
+#pragma once
 
 #include "vulkan.h"
 #include <stdbool.h>
@@ -258,5 +256,3 @@ typedef struct {
   VkIcdSurfaceBase base;
 } VkIcdSurfaceImagePipe;
 #endif // VK_USE_PLATFORM_FUCHSIA
-
-#endif  // VKICD_H

include/vulkan/vk_layer.h

@@ -19,12 +19,12 @@
  * limitations under the License.
  *
  */
+#pragma once
 
 /* Need to define dispatch table
  * Core struct can then have ptr to dispatch table at the top
  * Along with object ptrs for current and next OBJ
  */
-#pragma once
 
 #include "vulkan_core.h"
 

include/vulkan/vk_sdk_platform.h

@@ -18,9 +18,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
-#ifndef VK_SDK_PLATFORM_H
-#define VK_SDK_PLATFORM_H
+#pragma once
 
 #if defined(_WIN32)
 #ifndef NOMINMAX
@@ -67,5 +65,3 @@
 #define NOEXCEPT
 #endif
 #endif
-
-#endif  // VK_SDK_PLATFORM_H