Tessellation partial implementation (not ready for use yet), including:

- the built-in constants
 - built-in variable declarations, some dependent on gl_MaxPatchVertices
 - layout qualifier for vertices (shared with geometry shader max_vertices)
 - layout qualifiers for vertex spacing, vertex order, point mode, and primitive type
 - link semantics for layout qualifiers

Still TBD:
 - patch qualifier and arrayed input handling
 - sizing of gl_out[]
 - additional semantic checking
 - supporting the extension on version 150

git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@24468 e7fa87d3-cd2b-0410-9028-fcbf551c1848

Test/420.vert

@@ -71,9 +71,9 @@ layout(binding = 1) in inblock { int aoeua; };       // ERROR
 layout(binding = 100000) uniform anonblock2 { int aooeu; } ;
 layout(binding = 4) uniform sampler2D sampb1;
 layout(binding = 5) uniform sampler2D sampb2[10];
-layout(binding = 32) uniform sampler2D sampb3; // ERROR, binding too big
+layout(binding = 80) uniform sampler2D sampb3; // ERROR, binding too big
 layout(binding = 31) uniform sampler2D sampb4;
-layout(binding = 31) uniform sampler2D sampb5[2]; // ERROR, binding too big
+layout(binding = 79) uniform sampler2D sampb5[2]; // ERROR, binding too big
 
 int fgfg(float f, mediump int i);
 int fgfg(float f, highp int i);