Summary of problem description

GDCM compatibility

actual behaviour

cmake FIND_PACKAGE not called for GDCM

expected behaviour

call FIND_PACKAGE in case of system gdcm use

Cause of the bug

(How could this happen?, what went wrong?) not implemented

Proposed solution

(How do I plan to fix this? Other solutions?) see patch

Affected classes

(Which classes will be modified?, Which other classes/modules could be affected by the proposed change?) build system

How will the bugfix get tested?

(unit test possible?, manual test necessary? how can it be tested?)