[COFF][LTO][NPM] Use NPM for LTO with ENABLE_EXPERIMENTAL_NEW_PASS_MANAGER

lld/COFF/Driver.cpp

 #include "lld/Common/ErrorHandler.h"
 #include "lld/Common/Filesystem.h"
 #include "lld/Common/Memory.h"
 #include "lld/Common/Timer.h"
 #include "lld/Common/Version.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/BinaryFormat/Magic.h"
+#include "llvm/Config/llvm-config.h"
 #include "llvm/LTO/LTO.h"
 #include "llvm/Object/ArchiveWriter.h"
 #include "llvm/Object/COFFImportFile.h"
 #include "llvm/Object/COFFModuleDefinition.h"
 #include "llvm/Object/WindowsMachineFlag.h"
 #include "llvm/Option/Arg.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Option/Option.h"
void LinkerDriver::link(ArrayRef<const char *> argsArr) {
   if (auto *arg = args.getLastArg(OPT_implib))
     config->implib = arg->getValue();
 
   // Handle /opt.
   bool doGC = debug == DebugKind::None || args.hasArg(OPT_profile);
   unsigned icfLevel =
       args.hasArg(OPT_profile) ? 0 : 1; // 0: off, 1: limited, 2: on
   unsigned tailMerge = 1;
-  bool ltoNewPM = false;
+  bool ltoNewPM = LLVM_ENABLE_NEW_PASS_MANAGER;
   bool ltoDebugPM = false;
   for (auto *arg : args.filtered(OPT_opt)) {
     std::string str = StringRef(arg->getValue()).lower();
     SmallVector<StringRef, 1> vec;
     StringRef(str).split(vec, ',');
     for (StringRef s : vec) {
       if (s == "ref") {
         doGC = true;