Including BSD-licensed code in Mozilla

I have some BSD-licensed code which I'd like to include in NSPR,
specifically:
http://www.gnu-darwin.org/shims/inet_addr.c

How is this traditionally done? Asking the author to relicense is not
an option. Which leaves us with
a) include it in a trilicensed NSPR file, with the BSD license pasted
and a comment indicating that the BSD license pertains to that
function only;
b) include it as a separate, BSD-licensed file;
c) rewrite the code.

There is apparently some precedent for a) viz.
http://mxr.mozilla.org/mozilla-central/source/nsprpub/pr/src/misc/prdtoa.c.

Many thanks,
Dan.