Milter-greylist

Hello,

On my system there is no strndup function.
I got compilation warning (missing function prototype)
and linking error.

On an other system I found the following info (Linux man page of strndup):

CONFORMING TO
       strdup() conforms to SVr4, 4.3BSD, POSIX.1-2001.  strndup(), strdupa(), and strndupa() are GNU extensions.

Is there a way that the configure script checks for it  (inject HAVE_STRNDUP macro),
and if there is no such function a small additional function in milter-greylist.c?

Best,
Attila