uclibc: fix coreutils cut bug, enable needed config symbols

Symbols needed for all versions/flavours of uClibc.

Fixes https://bugs.buildroot.org/show_bug.cgi?id=4099



Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>