i think erase that directory and untar again and do at least
./build slx
to designate Linux or better yet (what worked on my system was)
Code:
./build DEBUG=-O MAILSPOOL=/var/mail SSLDIR=/usr SSLCERTS=/etc/ssl/certs slx
check at least what your actual maildir is
see doc/pine-ports file for more information and other authentication options
then of course
cd bin
install pine imapd ipop2d ipop3d mailutil mtest pico pilot rpdump rpload /usr/bin
hope that works better