curl: remove ac_cv_func_setmode override
curl: remove ac_cv_func_setmode override

this was added 717efee8f184038 by syncing from cygwin,
but cygwin no longer does this and it builds fine here.

JPeterMugaas/MSYS2-packages,JPeterMugaas/MSYS2-packages,JPeterMugaas/MSYS2-packages,JPeterMugaas/MSYS2-packages