cloexec: preserve text vs. binary across dup_cloexec On mingw, dup_cloexec mistakenly converted a text fd into a binary fd. Cygwin copied the source mode. Most other platforms don't distinguish between modes. * lib/cloexec.c (dup_cloexec) [W32]: Query and use translation mode. * modules/dup2-tests (Depends-on): Add binary-io. * modules/cloexec-tests (Depends-on): Likewise. * tests/test-dup2.c (setmode, is_mode): New helpers. (main): Add tests that translation mode is preserved. * tests/test-cloexec.c (setmode, is_mode, main): Likewise. Reported by Bruno Haible. Signed-off-by: Eric Blake <ebb9@byu.net>