Don't use ASTContext in DeclOpenMP.h because it's still incomplete.

llvm-svn: 352919
diff --git a/clang/lib/AST/DeclOpenMP.cpp b/clang/lib/AST/DeclOpenMP.cpp
index 5a1b036..39cb467 100644
--- a/clang/lib/AST/DeclOpenMP.cpp
+++ b/clang/lib/AST/DeclOpenMP.cpp
@@ -172,6 +172,16 @@
   std::uninitialized_copy(CL.begin(), CL.end(), Clauses.data());
 }
 
+OMPDeclareMapperDecl *OMPDeclareMapperDecl::getPrevDeclInScope() {
+  return cast_or_null<OMPDeclareMapperDecl>(
+      PrevDeclInScope.get(getASTContext().getExternalSource()));
+}
+
+const OMPDeclareMapperDecl *OMPDeclareMapperDecl::getPrevDeclInScope() const {
+  return cast_or_null<OMPDeclareMapperDecl>(
+      PrevDeclInScope.get(getASTContext().getExternalSource()));
+}
+
 //===----------------------------------------------------------------------===//
 // OMPCapturedExprDecl Implementation.
 //===----------------------------------------------------------------------===//