GSubprocess win32 fixups

Note: we go out of our way not to pass a child setup function on win32
(even if it does nothing) because we get a g_warning() from gspawn if we
do so.

gio/gwin32inputstream.c

@@ -31,6 +31,7 @@
 #include "gioerror.h"
 #include "gsimpleasyncresult.h"
 #include "gwin32inputstream.h"
+#include "giowin32-priv.h"
 #include "gcancellable.h"
 #include "gasynchelper.h"
 #include "glibintl.h"