It is usually used during marshalling, where pStubMsg->BufferStart and 
pStubMsg->BufferEnd won't be valid. Replace it with a check using 
RpcMsg->Buffer and pStubMsg->BufferLength.

aligns contains padding, but the memory is marshalled in one block so 
call memset to avoid Valgrind warnings. padded and padded2 are 
marshalled as complex types so this is not required here.

Initialise the dummy member of test_list_t to zero for the TL_NULL case. 
Change the type to the smallest available to not waste buffer space.

Also clear memory when FC_STRUCTPAD* is encountered.

Only do the clearing when marshalling a base type.

widl: The detection of types is highly dependent on the ordering of the various type detection functions.

Therefore, needs_freeing would have to duplicate a lot of
write_remoting_arg in order to get the detection right. Because of
this, it is easier and will cause less problems in the future to
simply move the logic of needs_freeing into write_remoting_arg in the
appropriate handling code for the detected type.

We can check this flag before setting up the gl lock, and add the
surface format to the FIXME.

This is to allow completions to be sent on handle close. Also this can
be helpful for AcceptEx/TransmitFile implementation.