哪位高人帮我看看qmail里这是什么错误呀

sunke1314520

我make set check 是每次都出现如下错误
nroff -man dot-qmail.5 > dot-qmail.0
nroff -man qmail-command.8 > qmail-command.0
nroff -man tcp-environ.5 > tcp-environ.0
nroff -man maildir.5 > maildir.0
nroff -man mbox.5 > mbox.0
nroff -man addresses.5 > addresses.0
nroff -man envelopes.5 > envelopes.0
nroff -man forgeries.7 > forgeries.0
./load digest passwd.o digest_md4.o digest_md5.o digest_rmd160.o \
digest_sha1.o base64.o qldap-debug.o output.o getopt.a strerr.a \
substdio.a case.a env.a stralloc.a str.a fs.a alloc.a error.a \
-lcrypt -lshadow
/usr/bin/ld: cannot find -lshadow
collect2: ld returned 1 exit status
make: *** [digest] Error 1