Linux PAM make err : undefine yywrap()问题

./configure  -> ok

make   ->   error[2]

pam_conv_l.o: In function `yylex':
/usr/local/justin/pam/Linux-PAM-1.6.0/conf/pam_conv1/pam_conv_l.c:843: undefined reference to `yywrap'
collect2: ld returned 1 exit status
make[4]: *** [pam_conv1] Error 1
make[4]: Leaving directory `/usr/local/tars/slackbuild/pam/Linux-PAM-0.99.10.0/conf/pam_conv1'
make[3]: *** [all] Error 2
make[3]: Leaving directory `/usr/local/tars/slackbuild/pam/Linux-PAM-0.99.10.0/conf/pam_conv1'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/usr/local/tars/slackbuild/pam/Linux-PAM-0.99.10.0/conf'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/usr/local/tars/slackbuild/pam/Linux-PAM-0.99.10.0'
make: *** [all] Error 2

原因是：安装flex库后，需要指定--with-libiconv-prefix=/usr

# ./configure --prefix=/user --exec-prefix=/usr --localstatedir=/var --sysconfdir=/etc --disable-selinux --with-libiconv-prefix=/usr