[OPENMP 5.0]Add initial support for 'allocate' directive.

Added parsing/sema analysis/serialization/deserialization support for
'allocate' directive.

llvm-svn: 355614
diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index a44c839..e1b5161 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -812,6 +812,7 @@
     case ObjCCategoryImpl:
     case Import:
     case OMPThreadPrivate:
+    case OMPAllocate:
     case OMPRequires:
     case OMPCapturedExpr:
     case Empty: