Added missing GNU Autoconf support to "tests".

Updated configure files for upcoming release.

DCMTK Public Minor Release 3.6.8

DCMTK Public Minor Release 3.6.7

Backport of TLS extensions to DCMTK 3.6.5.

DCMTK Public Minor Release 3.6.6

DCMTK Interim Tag

DCMTK Public Minor Release 3.6.5

DCMTK Public Minor Release 3.6.4

DCMTK Public Minor Release 3.6.3