Revert "Revert "GL_ext_vulkan_glsl_relaxed extension support, and cross stage aware IO mapper""

Test/iomap.crossStage.2.geom

@@ -0,0 +1,39 @@
+#version 460
+
+layout(points) in;
+layout(triangle_strip, max_vertices=3) out;
+
+in vec4 vgo1[];
+in vec2 vgo2[];
+
+layout(location = 5) in outBlock {
+    vec4 o3;
+} inBlock[];
+
+out vec4 gfo1;
+out vec2 gfo2;
+
+layout(location = 5) out outBlock {
+    vec4 o3;
+} gf_out;
+
+uniform vec2 u1;
+uniform vec3 u2 = vec3(0); // initializer not present in fragment stage
+uniform vec4 u3 = vec4(0); // initializer matches initializer in fragment stage
+
+uniform crossStageBlock2 {
+    uniform vec4 a;
+    vec2 b;
+} blockName1 [2]; // instance name different from frag
+
+void main()
+{
+    for (int i = 0; i < 3; i++) {
+        gfo1 = vec4(0);
+        gfo2 = vec2(0);
+        gf_out.o3 = inBlock[i].o3;
+        EmitVertex();
+    }
+    EndPrimitive();
+}
+