Missing/Differences from MS ATL headers

I seem to have noticed some missing/not working ATL functions/macros while trying to build an ATL project with ReactOS headers. None of this are required or similar changes I just wanted to notice some differences between MS ATL and ReactOS ATL headers.

1. _ATL_IIDOF does not exist (or at least I can't find it anywhere)
This gave me compilation errors on the function COM_INTERFACE_ENTRY
2. ATL::CAtlDllModuleT does not include a WinMain function.
Altrough it's mostly a stub unless a debug build it's being run the function does exist in MS ATL
3. ATL_NO_VTABLE generates an error/warning with GCC
message: "'novtable' attribute directive ignored"