Expose core metadata validation functions in public headers
diff --git a/binding.gyp b/binding.gyp
index 75e2f3c..d18d28e 100644
--- a/binding.gyp
+++ b/binding.gyp
@@ -269,6 +269,7 @@
         'src/core/surface/server.c',
         'src/core/surface/server_chttp2.c',
         'src/core/surface/server_create.c',
+        'src/core/surface/validate_metadata.c',
         'src/core/surface/version.c',
         'src/core/transport/byte_stream.c',
         'src/core/transport/chttp2/alpn.c',