Fix build failure.

Author: TIFitis

flang/include/flang/Lower/OpenMP.h

@@ -41,6 +41,7 @@ struct OmpClauseList;
 
 namespace semantics {
 class Symbol;
+class Scope;
 class SemanticsContext;
 } // namespace semantics
 

flang/lib/Semantics/resolve-names.cpp

@@ -1886,11 +1886,12 @@ void OmpVisitor::ProcessMapperSpecifier(const parser::OmpMapperSpecifier &spec,
   auto &mapperName{std::get<std::string>(spec.t)};
   // Create or update the mapper symbol with MapperDetails and
   // keep track of the declarative construct for module emission.
-  Symbol &mapperSym{MakeSymbol(parser::CharBlock(mapperName), Attrs{})};
-  if (auto *md{mapperSym.detailsIf<MapperDetails>()}) {
-    md->AddDecl(declaratives_.back());
-  } else if (mapperSym.has<UnknownDetails>() || mapperSym.has<MiscDetails>()) {
+  SourceName mapperSource{context().SaveTempName(std::string{mapperName})};
+  Symbol &mapperSym{MakeSymbol(mapperSource, Attrs{})};
+  if (!mapperSym.detailsIf<MapperDetails>()) {
     mapperSym.set_details(MapperDetails{});
+  }
+  if (!context().langOptions().OpenMPSimd) {
     mapperSym.get<MapperDetails>().AddDecl(declaratives_.back());
   }
   PushScope(Scope::Kind::OtherConstruct, nullptr);