Plumbing though mode parameter to open, since fusefs can make use of it.

native_client_sdk/src/libraries/nacl_io/httpfs/http_fs.cc

Index: native_client_sdk/src/libraries/nacl_io/httpfs/http_fs.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/httpfs/http_fs.cc b/native_client_sdk/src/libraries/nacl_io/httpfs/http_fs.cc
index 74e73838e1e8d540f27e5580c679ffbf937fb8a6..1950bb151210f39514d8b88df3bd5190e7ef1e4f 100644
--- a/native_client_sdk/src/libraries/nacl_io/httpfs/http_fs.cc
+++ b/native_client_sdk/src/libraries/nacl_io/httpfs/http_fs.cc
@@ -41,7 +41,8 @@ std::string NormalizeHeaderKey(const std::string& s) {
   return result;
 }
 
-Error HttpFs::Open(const Path& path, int open_flags, ScopedNode* out_node) {
+Error HttpFs::OpenWithMode(const Path& path, int open_flags, mode_t mode,
+                           ScopedNode* out_node) {
   out_node->reset(NULL);
 
   ScopedNode node = FindExistingNode(path);