Add support for gl_MaxVaryingVectors for ogl.

glslang/MachineIndependent/Initialize.cpp

@@ -7283,6 +7283,9 @@ void TBuiltIns::initialize(const TBuiltInResource &resources, int version, EProf
 
             snprintf(builtInConstant, maxSize, "const int  gl_MaxFragmentUniformVectors = %d;", resources.maxFragmentUniformVectors);
             s.append(builtInConstant);
+
+            snprintf(builtInConstant, maxSize, "const int  gl_MaxVaryingVectors = %d;", resources.maxVaryingVectors);
+            s.append(builtInConstant);
         }
 
         snprintf(builtInConstant, maxSize, "const int  gl_MaxVertexAttribs = %d;", resources.maxVertexAttribs);