Porting GL4 geometry shaders. Likely not working.

src/xenia/gpu/vulkan/shaders/quad_list.geom

@@ -0,0 +1,37 @@
+// NOTE: This file is compiled and embedded into the exe.
+//       Use `xenia-build genspirv` and check in any changes under bin/.
+
+#version 450
+#extension all : warn
+
+in gl_PerVertex {
+  vec4 gl_Position;
+  float gl_PointSize;
+  float gl_ClipDistance[];
+} gl_in[];
+
+out gl_PerVertex {
+  vec4 gl_Position;
+  float gl_PointSize;
+  float gl_ClipDistance[];
+};
+
+struct VertexData {
+  vec4 o[16];
+};
+layout(location = 1) in VertexData in_vtx[];
+layout(location = 1) out VertexData out_vtx;
+
+layout(lines_adjacency) in;
+layout(triangle_strip, max_vertices = 4) out;
+void main() {
+  const int order[4] = { 0, 1, 3, 2 };
+  for (int i = 0; i < 4; ++i) {
+    int input_index = order[i];
+    gl_Position = gl_in[input_index].gl_Position;
+    gl_PointSize = gl_in[input_index].gl_PointSize;
+    out_vtx = in_vtx[input_index];
+    EmitVertex();
+  }
+  EndPrimitive();
+}