libc: create an infrastructure to build and install the libc locales

This patch adds a common glibc/eglibc infrastructure to build and install the
libc locales.

Signed-off-by: "Benoît THÉBAUDEAU" <benoit.thebaudeau@advansee.com>

 reporter_name="Yann E. MORIN"

 reporter_url="http://ymorin.is-a-geek.org/dokuwiki/projects/crosstool"

 reporter_comment=""