Signed-off-by: Joel Holdsworth <joel@airwebreathe.org.uk>

dsound_private.h pulls in mediaobj.h, which previously pulled in strmif.h.
We were including that under the initguid.h, which meant that strmif.h GUIDs
were being defined in both dsound_main.o and uuid. Now that mediaobj.h does not
pull in strmif.h anymore, we don't need this include.

This means that mfobjects.idl no longer pulls in mediaobj.idl. Since it still
needs AM_MEDIA_TYPE to be declared (though not defined), add a typedef.

Reorder includes in a couple files to avoid multiple-definition errors.
strmiids and mfplat were getting strmif.h through mfobjects.h, and dsdmo was
getting it through dmo.h.

For IReferenceClock.

Currently we rely on it getting included via the following path:

wmsdk.idl
 -> wmsdkidl.idl
    -> drmexternals.idl
       -> wmdrmsdk.idl
          -> mfobjects.idl
             -> mediaobj.idl
                -> strmif.idl

However, mediaobj.idl should not pull in strmif.idl.

Signed-off-by: Nikolay Sivov <nsivov@codeweavers.com>

Signed-off-by: Nikolay Sivov <nsivov@codeweavers.com>

And move the remaining common ones to d3dxof_private.h, as is usual practice
with d3d dlls.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=38823

This makes muxer element know that it can perform seeking.