Add a std:: prefix in cases where ADL would have failed on windows.

This is in preparation for removing make_error_code from the llvm namespace.

llvm-svn: 210745
diff --git a/clang/lib/Basic/VirtualFileSystem.cpp b/clang/lib/Basic/VirtualFileSystem.cpp
index 27b6c75..edc8bbb 100644
--- a/clang/lib/Basic/VirtualFileSystem.cpp
+++ b/clang/lib/Basic/VirtualFileSystem.cpp
@@ -201,7 +201,7 @@
     if (Status || Status.getError() != std::errc::no_such_file_or_directory)
       return Status;
   }
-  return make_error_code(std::errc::no_such_file_or_directory);
+  return std::make_error_code(std::errc::no_such_file_or_directory);
 }
 
 error_code OverlayFileSystem::openFileForRead(const llvm::Twine &Path,
@@ -212,7 +212,7 @@
     if (!EC || EC != std::errc::no_such_file_or_directory)
       return EC;
   }
-  return make_error_code(std::errc::no_such_file_or_directory);
+  return std::make_error_code(std::errc::no_such_file_or_directory);
 }
 
 //===-----------------------------------------------------------------------===/
@@ -744,7 +744,7 @@
     return EC;
 
   if (Path.empty())
-    return make_error_code(std::errc::invalid_argument);
+    return std::make_error_code(std::errc::invalid_argument);
 
   sys::path::const_iterator Start = sys::path::begin(Path);
   sys::path::const_iterator End = sys::path::end(Path);
@@ -754,7 +754,7 @@
     if (Result || Result.getError() != std::errc::no_such_file_or_directory)
       return Result;
   }
-  return make_error_code(std::errc::no_such_file_or_directory);
+  return std::make_error_code(std::errc::no_such_file_or_directory);
 }
 
 ErrorOr<Entry *> VFSFromYAML::lookupPath(sys::path::const_iterator Start,
@@ -767,7 +767,7 @@
   if (CaseSensitive ? !Start->equals(From->getName())
                     : !Start->equals_lower(From->getName()))
     // failure to match
-    return make_error_code(std::errc::no_such_file_or_directory);
+    return std::make_error_code(std::errc::no_such_file_or_directory);
 
   ++Start;
 
@@ -778,7 +778,7 @@
 
   DirectoryEntry *DE = dyn_cast<DirectoryEntry>(From);
   if (!DE)
-    return make_error_code(std::errc::not_a_directory);
+    return std::make_error_code(std::errc::not_a_directory);
 
   for (DirectoryEntry::iterator I = DE->contents_begin(),
                                 E = DE->contents_end();
@@ -787,7 +787,7 @@
     if (Result || Result.getError() != std::errc::no_such_file_or_directory)
       return Result;
   }
-  return make_error_code(std::errc::no_such_file_or_directory);
+  return std::make_error_code(std::errc::no_such_file_or_directory);
 }
 
 ErrorOr<Status> VFSFromYAML::status(const Twine &Path) {
@@ -820,7 +820,7 @@
 
   FileEntry *F = dyn_cast<FileEntry>(*E);
   if (!F) // FIXME: errc::not_a_file?
-    return make_error_code(std::errc::invalid_argument);
+    return std::make_error_code(std::errc::invalid_argument);
 
   if (error_code EC = ExternalFS->openFileForRead(F->getExternalContentsPath(),
                                                   Result))