Add support for getting the last modification time from a file_status.

Use that in llvm-ar.cpp to replace a use of sys::PathWithStatus.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184450 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-ar/llvm-ar.cpp b/tools/llvm-ar/llvm-ar.cpp
index 4c98671..e422f31 100644
--- a/tools/llvm-ar/llvm-ar.cpp
+++ b/tools/llvm-ar/llvm-ar.cpp
@@ -583,15 +583,14 @@
     }
 
     if (found != remaining.end()) {
-      std::string Err;
-      sys::PathWithStatus PwS(*found);
-      const sys::FileStatus *si = PwS.getFileStatus(false, &Err);
-      if (!si)
+      sys::fs::file_status Status;
+      error_code EC = sys::fs::status(*found, Status);
+      if (EC)
         return true;
-      if (!si->isDir) {
+      if (!sys::fs::is_directory(Status)) {
         if (OnlyUpdate) {
           // Replace the item only if it is newer.
-          if (si->modTime > I->getModTime())
+          if (Status.getLastModificationTime() > I->getModTime())
             if (I->replaceWith(*found, ErrMsg))
               return true;
         } else {