Segmentation fault when -x is added and variable contains nulls

[Dan Jacobson]

# su - nobody
No directory, logging in with HOME=/
$ cat /tmp/r
LC_CTYPE=zh_TW.UTF-8 N=$(echo 統一|iconv -t big5 -f utf-8) sh -xc ': $N'
$ sh /tmp/r
/tmp/r: line 1:  4551 Segmentation fault      LC_CTYPE=zh_TW.UTF-8 N=$(echo 
統一|iconv -t big5 -f utf-8) sh -xc ': $N'

Something about that embedded null.
bash, version 4.3.0(1)-rc1 (i486-pc-linux-gnu)