libc/uClibc: do not systematically use pre-generated locale data

It seems that using pre-generated locale data can be more problematic
than usefull in some circumstances.

Offer a config knob to enable/disable use of the pregen locale data.
Also, do not extract pregen locales data ourselves, it's broken.

 reporter_name="YEM"

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

 reporter_comment="EXPERIMENTAL Super-H sh4 sample."