The localedef utility has trouble processing the CP1255 character set description file:
$ (export RWSTD_SRC_ROOT=/nfs/devco/sebor/stdcxx/etc/nls; \
mkdir -p /tmp/$$ \
&& ./localedef -w -c -f $RWSTD_SRC_ROOT/charmaps/CP1255 -i $RWSTD_SRC_ROOT/src/yi_US /tmp/$$/yi_US.CP1255)
Error 308: illegal multibyte prefix '\x90' in character map file
STDCXX-373where this came up.