need ldap-int.h for ldap_int_discard() declaration (ITS#4717)

servers/slapd/back-ldap/bind.c

@@ -32,6 +32,8 @@
 #define AVL_INTERNAL
 #include "slap.h"
 #include "back-ldap.h"
+#undef ldap_debug	/* silence a warning in ldap-int.h */
+#include "../../../libraries/libldap/ldap-int.h"
 
 #include "lutil_ldap.h"