Salieri: shader cache (#1701)

Here come Salieri, my implementation of a disk shader cache!

"I'm sure you know why I named it that."
"It doesn't really mean anything."

This implementation collects shaders at runtime and cache them to be later compiled when starting a game.

Ryujinx.Graphics.Gpu/Shader/Cache/Definition/GuestShaderCacheTransformFeedbackHeader.cs

@@ -0,0 +1,38 @@
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.Graphics.Gpu.Shader.Cache.Definition
+{
+    /// <summary>
+    /// Header for transform feedback.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential, Pack = 1, Size = 0x10)]
+    struct GuestShaderCacheTransformFeedbackHeader
+    {
+        /// <summary>
+        /// The buffer index of the transform feedback.
+        /// </summary>
+        public int BufferIndex;
+
+        /// <summary>
+        /// The stride of the transform feedback.
+        /// </summary>
+        public int Stride;
+
+        /// <summary>
+        /// The length of the varying location buffer of the transform feedback.
+        /// </summary>
+        public int VaryingLocationsLength;
+
+        /// <summary>
+        /// Reserved/unused.
+        /// </summary>
+        public int Reserved1;
+
+        public GuestShaderCacheTransformFeedbackHeader(int bufferIndex, int stride, int varyingLocationsLength) : this()
+        {
+            BufferIndex = bufferIndex;
+            Stride = stride;
+            VaryingLocationsLength = varyingLocationsLength;
+        }
+    }
+}