shader: Implement transform feedbacks and define file format

src/shader_recompiler/profile.h

@@ -5,6 +5,7 @@
 #pragma once
 
 #include <array>
+#include <vector>
 #include <optional>
 
 #include "common/common_types.h"
@@ -26,6 +27,13 @@ enum class InputTopology {
     TrianglesAdjacency,
 };
 
+struct TransformFeedbackVarying {
+    u32 buffer{};
+    u32 stride{};
+    u32 offset{};
+    u32 components{};
+};
+
 struct Profile {
     u32 supported_spirv{0x00010000};
 
@@ -58,6 +66,8 @@ struct Profile {
     InputTopology input_topology{};
 
     std::optional<float> fixed_state_point_size;
+
+    std::vector<TransformFeedbackVarying> xfb_varyings;
 };
 
 } // namespace Shader