Reinstate one check, fix fall out
diff --git a/binding.gyp b/binding.gyp
index f1cef60..e01142d 100644
--- a/binding.gyp
+++ b/binding.gyp
@@ -700,7 +700,7 @@
         'src/core/lib/json/json_reader.c',
         'src/core/lib/json/json_string.c',
         'src/core/lib/json/json_writer.c',
-        'src/core/lib/security/util/b64.c',
+        'src/core/lib/slice/b64.c',
         'src/core/lib/slice/percent_encoding.c',
         'src/core/lib/slice/slice.c',
         'src/core/lib/slice/slice_buffer.c',