Add basic detection for db3

build/openldap.m4

@@ -265,7 +265,9 @@ AC_DEFUN([OL_BERKELEY_DB_TRY],
 #define NULL ((void*)0)
 #endif
 ],[
-#if DB_VERSION_MAJOR > 1
+#if DB_VERSION_MAJOR > 2
+	db_env_create( NULL, 0 );
+#elif DB_VERSION_MAJOR > 1
 	db_appexit( NULL );
 #else
 	(void) dbopen( NULL, 0, 0, 0, NULL);

configure.in

@@ -1723,8 +1723,6 @@ if test $ol_with_ldbm_api = auto \
 	fi
 fi
 
-exit
-
 if test $ol_link_ldbm = no -a $ol_with_ldbm_type = btree ; then
 	AC_MSG_WARN(Could not find LDBM with BTREE support)
 	ol_with_ldbm_api=none