pgevent warnings on mingw

I just noticed these warnings on pgevent/mingw. I guess we've probably 
been living with it for years, but it would be nice to get it clean. 
(There are also some similar warnings earlier in the build regarding 
RegisterWaitForSingleObject.)

dllwrap --def pgevent.def -o pgevent.dll pgevent.o pgmsgevent.o
Warning: resolving _DllUnregisterServer by linking to _DllUnregisterServer@0
Use --enable-stdcall-fixup to disable these warnings
Use --disable-stdcall-fixup to disable these fixups
Warning: resolving _DllRegisterServer by linking to _DllRegisterServer@0
Warning: resolving _DllUnregisterServer by linking to _DllUnregisterServer@0
Use --enable-stdcall-fixup to disable these warnings
Use --disable-stdcall-fixup to disable these fixups
Warning: resolving _DllRegisterServer by linking to _DllRegisterServer@0

What do we have to do to clean this stuff up?

cheers

andrew