SPV: Implement Vulkan version of GLSL (KHR_vulkan_glsl).

Test/spv.flowControl.frag

@@ -1,8 +1,8 @@
 #version 140
 
-uniform float d;
-uniform vec4 bigColor, smallColor;
-uniform vec4 otherColor;
+in float d;
+in vec4 bigColor, smallColor;
+in vec4 otherColor;
 
 in float c;
 in vec4 BaseColor;