[MachO] Add undefined atoms.

llvm-svn: 200649
diff --git a/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp b/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp
index b91e3a8..c84ca77 100644
--- a/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp
+++ b/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp
@@ -98,8 +98,9 @@
     processSymbol(normalizedFile, *file, sym, copyRefs);
   }
 
-  assert(normalizedFile.undefinedSymbols.empty() &&
-         "undefined symbols not supported yet!");
+  for (auto &sym : normalizedFile.undefinedSymbols) {
+    file->addUndefinedAtom(sym.name, copyRefs);
+  }
 
   return std::unique_ptr<File>(std::move(file));
 }