Change err_pp_file_not_found back to an Error; when it's a Warning, we suppress it in system headers.  And it is not a good idea to suppress it in system headers.  (This was originally changed in r134996 to implement -MG.)

Fixes <rdar://10041960>.  And also brings down the number of warnings without a flag by one :)



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@138842 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/DependencyFile.cpp b/lib/Frontend/DependencyFile.cpp
index 8435864..db43ab9 100644
--- a/lib/Frontend/DependencyFile.cpp
+++ b/lib/Frontend/DependencyFile.cpp
@@ -86,14 +86,8 @@
   }
 
   // Disable the "file not found" diagnostic if the -MG option was given.
-  // FIXME: Ideally this would live in the driver, but we don't have the ability
-  // to remap individual diagnostics there without creating a DiagGroup, in
-  // which case we would need to prevent the group name from showing up in
-  // diagnostics.
-  if (Opts.AddMissingHeaderDeps) {
-    PP.getDiagnostics().setDiagnosticMapping(diag::warn_pp_file_not_found,
-                                            diag::MAP_IGNORE, SourceLocation());
-  }
+  if (Opts.AddMissingHeaderDeps)
+    PP.SetSuppressIncludeNotFoundError(true);
 
   PP.addPPCallbacks(new DependencyFileCallback(&PP, OS, Opts));
 }