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

Test/iomap.crossStage.vk.frag

@@ -0,0 +1,50 @@
+#version 460
+
+
+layout(location = 5) in outBlock {
+    vec4 o3;
+};
+
+
+in vec4 gfo1;
+in vec2 gfo2;
+
+out vec4 outColor;
+
+layout (binding = 0) uniform sampler2D glass;
+
+uniform crossStageBlock1 {
+    uniform vec4 a;
+    vec4 b;
+};
+
+readonly buffer fragOnlyBlock {
+    vec2 fb1;
+};
+
+uniform crossStageBlock2 {
+    uniform vec4 a;
+    vec2 b;
+} blockName2 [2]; // instance name different from vert
+
+vec2 Bar() {
+    return  fb1 + 
+            blockName2[0].b +
+            blockName2[1].b;
+}
+
+vec4 Foo() {
+    return  a + 
+            b + 
+            blockName2[0].a +
+            blockName2[1].a +
+            vec4(Bar(), 0.0, 0.0);
+}
+
+void main()
+{
+    vec4 color = gfo1; // o1 is statically used
+    color = color + Foo();
+    outColor = color;
+}
+