We have no Windows critters contributing typedef lists

A pgindent run I just did showed me that we no longer have entries in
the buildfarm's typedefs list for any typedefs that are used only in
EXEC_BACKEND builds --- and, I suppose, none for Windows-only code
either.  I suppose that one of the recently deceased Windows animals
was the only one contributing those.  We need to improve this situation
before it's time to run pgindent again.

I'm not sure what the infrastructure requirements are for extracting
typedefs from Windows builds.

            regards, tom lane