[OPENMP] FIx processing of declare target variables.

The compiler may produce unexpected error messages/crashes when declare
target variables were used. Patch fixes problems with the declarations
marked as declare target to or link.

llvm-svn: 339805
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index 2d90c98..8eb6c61 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -2237,8 +2237,7 @@
 
   // File scoped assembly or obj-c or OMP declare target implementation must be
   // seen.
-  if (isa<FileScopeAsmDecl>(D) || isa<ObjCImplDecl>(D) ||
-      D->hasAttr<OMPDeclareTargetDeclAttr>())
+  if (isa<FileScopeAsmDecl>(D) || isa<ObjCImplDecl>(D))
     return true;
 
   if (WritingModule && (isa<VarDecl>(D) || isa<ImportDecl>(D))) {