as discussed in the thread starting at
https://sourceware.org/ml/libc-alpha/2015-06/msg00098.html
it looks like the best options is to remove locale timezone information
from locales which currently provide it (in incomplete or incorrect
fashion) rather than to start duplicating tzdata info in glibc.
2005-09-25 Ulrich Drepper <drepper@redhat.com>
[BZ #714]
* iconv/loop.c [!STORE_REST] (SINGLE): Correctly record number of
left-over bytes and store them correctly.
* iconvdata/tst-iconv6.c: New file.
* iconvdata/Makefile (tests): Add tst-iconv6.