[OPENMP 4.0] Initial support for array sections.

Adds parsing/sema analysis/serialization/deserialization for array sections in OpenMP constructs (introduced in OpenMP 4.0).
Currently it is allowed to use array sections only in OpenMP clauses that accepts list of expressions.
Differential Revision: http://reviews.llvm.org/D10732

llvm-svn: 245937
diff --git a/clang/lib/AST/ExprClassification.cpp b/clang/lib/AST/ExprClassification.cpp
index 9cc612e..882c786 100644
--- a/clang/lib/AST/ExprClassification.cpp
+++ b/clang/lib/AST/ExprClassification.cpp
@@ -136,6 +136,7 @@
   case Expr::ObjCIvarRefExprClass:
   case Expr::FunctionParmPackExprClass:
   case Expr::MSPropertyRefExprClass:
+  case Expr::OMPArraySectionExprClass:
     return Cl::CL_LValue;
 
     // C99 6.5.2.5p5 says that compound literals are lvalues.