Add Findlibffi.cmake master branch (2018.03.13.)
Added a Findlibffi.cmake
module, since the glib version that we set up from LCG_91 (and newer versions) depends on libffi coming with LCG as well.
This is to prepare the fix for ATLINFR-2270. But the full fix will need an update in atlas/athena master as well...
Edited by Emil Obreshkov