libc/glibc: print name of skipped addon

When trying to extract an already present (aka bundled) addon,
print the name of that addon, for clarity, and to help analyse
the build.log post-mortem.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

#!/bin/sh

set -e

printf "Running autoconf...\n"

autoconf -Wall --force

printf "Done. You may now run:\n    ./configure\n"