I finally figured out how to do this. This diff allow www/apache2 to be 
built with LDAP support (databases/openldap). I'm no pkgsrc guru, so 
some other people might have some enlightening comments on what I've 
done and come up with some improvements.

Daniel

*** Makefile.org        Sun Apr 20 17:27:55 2003
--- Makefile    Sun Apr 20 22:21:16 2003
***************
*** 49,54 ****
--- 50,66 ----

   APACHE_USER?= www
   APACHE_GROUP?=        www
+
+ .if defined(APACHE_AUTH_LDAP) && ${APACHE_AUTH_LDAP} == YES
+ .include "../../databases/openldap/buildlink2.mk"
+ APACHE_LDAP_CONFIGURE_ARGS+=                                          
\
+                       --with-ldap                                     
\
+                       
--with-ldap-include=${BUILDLINK_PREFIX.openldap}/include \
+                       --with-ldap-lib=${BUILDLINK_PREFIX.openldap}/lib
+ APACHE_MODULES+=      auth_ldap ldap
+ CONFIGURE_ARGS+=      ${APACHE_LDAP_CONFIGURE_ARGS:M--with-ldap*}
+ BUILD_DEFS+=          APACHE_AUTH_LDAP APACHE_LDAP_CONFIGURE_ARGS
+ .endif

   SUEXEC_COMMENT?=      "@comment "
   .if defined(APACHE_SUEXEC) && ${APACHE_SUEXEC} == YES