compile with pam ldap erroring

I am attempting to compile wu-ftpd 2.6.2 for solaris 8. I would like to 
enable pam.  Here is my configure options:

./configure --enable-pam --with-etc-dir=/usr/local/etc --prefix=/usr/local \
 --enable-ls

when I use the --enable-pam option, I get the following error once I execute
the make command:

ftpd.c:6979: warning: initialization from incompatible pointer type


I checked in the ftpd.c  at line 6979 and the following entry was there:

 &PAM_conv,



I have tried both gcc and Sun's cc compiler.

I have searched google, but nothing current or helpful comes up.

any help would be appreciated.

thanks regards,

Ron