VideoBackends / VideoCommon: add support for specifying include files in shader code

Source/Core/VideoBackends/Vulkan/VKShader.h

@@ -27,6 +27,7 @@ public:
   BinaryData GetBinary() const override;
 
   static std::unique_ptr<VKShader> CreateFromSource(ShaderStage stage, std::string_view source,
+                                                    VideoCommon::ShaderIncluder* shader_includer,
                                                     std::string_view name);
   static std::unique_ptr<VKShader> CreateFromBinary(ShaderStage stage, const void* data,
                                                     size_t length, std::string_view name);