It's fixed in quantal:
"libxslt (1.1.26-12) unstable; urgency=low ... * debian/control: mark libxslt1-dev as not M-A (Closes: #671902)."
It's fixed in quantal:
"libxslt (1.1.26-12) unstable; urgency=low
...
* debian/control: mark libxslt1-dev as not M-A (Closes: #671902)."