Add patch to fix uClibc build failure with locale enabled

This patch fixes the undefined reference to `__iconv_codesets'
reported at
http://www.mail-archive.com/uclibc@uclibc.org/msg04970.html

. The patch
has been taken from the upstream Git repository, and will be part of
uClibc 0.9.30.3. In the mean time, let's integrate it.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>