libldap/libldap_r confusion

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

The more I think about it, the more fundamental the problem appears to be.

If a library uses LDAP, i.e. libldap{,_r}, it can't know whether it will be
used in a threaded or non-threaded world. Should it link to libldap or to
libldap_r?