Add thunks for MojoGetRights(), etc.

mojo/public/platform/native/system_impl_private_thunks.c

Index: mojo/public/platform/native/system_impl_private_thunks.c
diff --git a/mojo/public/platform/native/system_impl_private_thunks.c b/mojo/public/platform/native/system_impl_private_thunks.c
index 466668592c65c602373a2ec4a7550b7e2c6903f1..82f2ac17d51c0618dffa458d8952a53bb8365f2c 100644
--- a/mojo/public/platform/native/system_impl_private_thunks.c
+++ b/mojo/public/platform/native/system_impl_private_thunks.c
@@ -41,6 +41,13 @@ MojoResult MojoSystemImplClose(MojoSystemImpl system, MojoHandle handle) {
   return g_system_impl_thunks.Close(system, handle);
 }
 
+MojoResult MojoSystemImplGetRights(MojoSystemImpl system,
+                                   MojoHandle handle,
+                                   MojoHandleRights* rights) {
+  assert(g_system_impl_thunks.GetRights);
+  return g_system_impl_thunks.GetRights(system, handle, rights);
+}
+
 MojoResult MojoSystemImplWait(MojoSystemImpl system,
                               MojoHandle handle,
                               MojoHandleSignals signals,