Support the synonyms for these and existing calling conventions.

Support automatically setting the calling convention to 
STDMETHODCALLTYPE if it is part of an object interface.

Write out the calling convention in write_type_v.

This clarifies its use in code and makes it simpler to change the way 
functions are parsed into types.

winex11: Move handling of WM_STATE changes to a separate function, and call it directly from wait_from_withdrawn_state.

Use FormatMessage to get the message for the Win32 error.