chore: add missing include (#3774)

diff --git a/kythe/cxx/common/kzip_writer_test.cc b/kythe/cxx/common/kzip_writer_test.cc
index df9e294..56501f5 100644
--- a/kythe/cxx/common/kzip_writer_test.cc
+++ b/kythe/cxx/common/kzip_writer_test.cc
@@ -19,6 +19,8 @@
 #include <zip.h>
 
 #include <cstdlib>
+#include <unordered_map>
+#include <unordered_set>
 
 #include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"