Compiling PROFTPD server in OpenIndiana OS

I am trying to compile Profptd-1.3.6 source code using GCC compiler on OpenIndiana OS. I have successfully configured the source code. However my Terminal window outputs the following error

    root@openindiana:~/proftpd#gmake
    .....
    .....
    .....
    gcc -DHAVE_CONFIG_H -DSOLARIS2_11 -DSOLARIS2 -I.. -I../include -g2 -O2 -Wall -fno-omit-frame-pointer -c mod_auth.c
    mod_auth.c: In function 'login_failed':
    mod_auth.c:356:9: warning: implicit declaration of function 'loginfailed' [-Wimplicit-function-declaration]
       res = loginfailed((char *) user, (char *) host, (char *) sess_ttyname,
             ^~~~~~~~~~~
    mod_auth.c:357:5: error: 'AUDIT_FAIL' undeclared (first use in this function)
         AUDIT_FAIL);
         ^~~~~~~~~~
    mod_auth.c:357:5: note: each undeclared identifier is reported only once for each function it appears in
    mod_auth.c:350:12: warning: variable 'xerrno' set but not used [-Wunused-but-set-variable]
       int res, xerrno;
                ^~~~~~
    mod_auth.c: In function 'login_succeeded':
    mod_auth.c:420:9: warning: implicit declaration of function 'loginsuccess' [-Wimplicit-function-declaration]
       res = loginsuccess((char *) user, (char *) host, (char *) sess_ttyname, &msg);
             ^~~~~~~~~~~~
    mod_auth.c:414:12: warning: variable 'xerrno' set but not used [-Wunused-but-set-variable]
       int res, xerrno;
                ^~~~~~
    gmake[1]: *** [Makefile:31: mod_auth.o] Error 1
    gmake[1]: Leaving directory '/export/home/grct/proftpd/modules'
    gmake: *** [Makefile:39: modules] Error 2
    root@openindiana:~/proftpd#

I dont know what to do to solve it?

thanks in advance for any help given