RELENG_6: cannot make buildworld

cc -O -pipe  -include nbsd2fbsd.h -I/usr/src/libexec/lukemftpd -I/usr/src/libexec/lukemftpd/../../contrib/lukemftpd -I/usr/src/libexec/lukemftpd/../../contrib/lukemftpd/src -I/usr/src/libexec/lukemftpd/../../lib/libc/stdtime -I/usr/src/libexec/lukemftpd/../../bin/ls -DUSE_OPIE -DLOGIN_CAP -DUSE_PAM   -static -o lukemftpd cmds.o conf.o ftpd.o ftpcmd.o popen.o strsuftoll.o ls-unmain.o cmp.o print.o util.o -lcrypt -lutil -lm -lopie -lmd -lpam -lkrb5 -lasn1 -lcrypto -lcrypt -lroken -lcom_err -lradius -ltacplus -lcrypt  -lutil -lopie -lmd -lssh -lcrypto -lcrypt
/usr/obj/usr/src/tmp/usr/lib/libssh.a(xmalloc.o)(.text+0xc8): In function `xstrdup':
: multiple definition of `xstrdup'
ftpd.o(.text+0x674c): first defined here
/usr/obj/usr/src/tmp/usr/bin/ld: Warning: size of symbol `xstrdup' changed from 47 in ftpd.o to 57 in /usr/obj/usr/src/tmp/usr/lib/libssh.a(xmalloc.o)
*** Error code 1

Stop in /usr/src/libexec/lukemftpd.

My /etc/make.conf:

# sed -E '/^#/d;s/#.*//' /etc/make.conf
CFLAGS= -O -pipe
COPTFLAGS= -O -pipe
MTREE_FOLLOWS_SYMLINKS= -L
NO_BLUETOOTH=           
NO_FORTRAN=             
NO_I4B=         
NO_INET6=               
NO_IPFILTER=            
NO_LPR=         
NO_NIS=         
NO_PROFILE=             
NO_SENDMAIL=            
NO_SHARED=              
NO_DYNAMICROOT=                 
SUP_UPDATE=
SUPHOST=        a.cvsup.sigpipe.cz
SUPFILE=        /usr/share/examples/cvsup/standard-supfile
PORTSSUPFILE=   /usr/share/examples/cvsup/ports-supfile
PERL_VER=5.8.7
PERL_VERSION=5.8.7


-- 
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You don't know, man.  You don't KNOW.
Cause you weren't THERE.             http://bash.org/?255991