I have not looked in depth at the uClibc timezone code, but tere are some notes taken from the "glibc vs. uClibc" readme file:
time functions
--------------
1) Leap seconds are not supported.
2) /etc/timezone and the whole zoneinfo directory tree are not supported.
To set the timezone, set the TZ environment variable as specified in
http://www.opengroup.org/onlinepubs/007904975/basedefs/xbd_chap08.html
or you may also create an /etc/TZ file of a single line, ending with a
newline, containing the TZ setting. For example
echo CST6CDT > /etc/TZ
3) Currently, locale specific eras and alternate digits are not supported.
They are on my TODO list.

wide char support
-----------------
1) The only multibyte encoding currently supported is UTF-8. The various
ISO-8859-* encodings are (optionally) supported. The internal
representation of wchar's is assumed to be 31 bit unicode values in
native endian representation. Also, the underlying char encoding is
assumed to match ASCII in the range 0-0x7f.
2) In the next iteration of locale support, I plan to add support for
(at least some) other multibyte encodings.

locale support
--------------
1) The target for support is SUSv3 locale functionality. While nl_langinfo
has been extended, similar to glibc, it only returns values for related
locale entries.
2) Currently, all SUSv3 libc locale functionality should be implemented
except for wcsftime and collating item support in regex.