build: move internals to separate header file
diff --git a/node.gyp b/node.gyp
index 9de3492..b4a3e46 100644
--- a/node.gyp
+++ b/node.gyp
@@ -125,6 +125,7 @@
       ],
 
       'defines': [
+        'NODE_WANT_INTERNALS=1',
         'ARCH="<(target_arch)"',
         'PLATFORM="<(OS)"',
       ],