+dnl Do you want client-side support for apop?
+dnl Note that this appears before pop so that we can enforce enable-pop
+AC_ARG_ENABLE(apop,
+[ --enable-apop enable client-side support for apop])
+if test x"$enable_apop" = x"yes"; then
+ AC_DEFINE(APOP)dnl
+ APOPLIB=md5.o
+ enable_pop=yes
+fi
+AC_SUBST(APOPLIB)dnl
+
+dnl Do you want support for hesiod
+AC_ARG_WITH(hesiod,
+[ --with-hesiod=PREFIX specify location of Hesiod])
+if test x"$with_hesiod" != x -a x"$with_hesiod" != x"no"; then
+ AC_DEFINE(HESIOD)dnl
+fi
+
+dnl Do you want client-side support for kpop
+AC_ARG_WITH(krb4,
+[ --with-krb4=PREFIX specify location of Kerberos V4 for kpop support])
+if test x"$with_krb4" != x -a x"$with_krb4" != x"no"; then
+ enable_pop=yes
+ AC_DEFINE(KPOP)dnl
+ AC_DEFINE(KPOP_PRINCIPAL, "pop")dnl
+fi
+