gn: Fix GN build warnings

BUILD.gn

diff --git a/BUILD.gn b/BUILD.gn
index fe551f4..a249ae6 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -56,6 +56,13 @@
     "include/vulkan/vulkan.hpp",
     "include/vulkan/vulkan_core.h",
     "include/vulkan/vulkan_screen.h",
+    "include/vk_video/vulkan_video_codec_h264std_decode.h",
+    "include/vk_video/vulkan_video_codec_h264std_encode.h",
+    "include/vk_video/vulkan_video_codec_h264std.h",
+    "include/vk_video/vulkan_video_codec_h265std_decode.h",
+    "include/vk_video/vulkan_video_codec_h265std_encode.h",
+    "include/vk_video/vulkan_video_codec_h265std.h",
+    "include/vk_video/vulkan_video_codecs_common.h",
   ]
   public_configs = [ ":vulkan_headers_config" ]
 }