Rename EvqConst to EvqConstExpr

In GLSL ES a variable declared const is a compile-time constant, and
thus a constant expression. Parameters declared const are read-only but
not compile-time constant.

Bug 19511934

Change-Id: I6d02062ca62c4185a3384b31a4d3ce8dfcc86b35
Reviewed-on: https://swiftshader-review.googlesource.com/2441
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
diff --git a/src/OpenGL/compiler/parseConst.cpp b/src/OpenGL/compiler/parseConst.cpp
index 563e39b..43e5c21 100644
--- a/src/OpenGL/compiler/parseConst.cpp
+++ b/src/OpenGL/compiler/parseConst.cpp
@@ -67,7 +67,7 @@
 {
     TQualifier qualifier = node->getType().getQualifier();
 
-    if (qualifier != EvqConst) {
+    if (qualifier != EvqConstExpr) {
         TString buf;
         buf.append("'constructor' : assigning non-constant to ");
         buf.append(type.getCompleteString());