The programs gen_ctype_from_glibc.c and gen_collate_from_glibc.c
will generate data files which can be
used by uClibc ctype, strcoll and setlocale functions to support locales.
From the comments:

/*
 * Generator locale ctype tables
 * You must have already setuped locale for worked libc (libc5 or glibc)
 *
 * This programm scan /usr/share/locale directories and write
 * ./LOCALE/LC_CTYPE files for system with uclibc
 *
 * Written by Vladimir Oleynik <vodz@usa.net> 2001
 */


Sample usage to dump all the data files in a tmp directory:

gcc gen_ctype_from_glibc.c -o gen_ctype_from_glibc
gcc gen_collate_from_glibc.c -o gen_ctype_from_glibc

mkdir tmp
cd tmp
../gen_ctype_from_glibc -d /usr/share/locale -c
../gen_collate_from_glibc

Then just move the directory or directories you need (not the .c files)
to the uClibc locale file directory you set in Config.