* configure.ac <adns>: Use adns_free as probe function for libadns.
(HAVE_ADNS_FREE): Remove bogus tests to set this and remove the macro.
(ADNSLIBS): Do not ac_subst - it is only used within configure.
--
adns_free is required on Windows anyway (for robustness reasons) and
it has been around for so long now that we do not need a separate
test. An upstream adns 1.5 has meanwhile been release but I doubt that
this has the required Windows code - and it is not libtool based
anyway.
We better do this once and for all instead of cluttering all future
commits with diffs of trailing white spaces. In the majority of cases
blank or single lines are affected and thus this change won't disturb
a git blame too much. For future commits the pre-commit scripts
checks that this won't happen again.