Removed FindXercesC now that new versions of Xerces are integrated with cmake

This merge request is needed on the LHCb side when we use the DD4hep geometry framework and does not harm otherwise in the head of master.

The key questions are :

• does it break some backward compatibility ?
• do other (Atlas ?) have trouble with this change ?

mentioned in merge request lhcb/LHCb!2455 (merged)

by "new CMake versions" you mean 3.1.3 :)

assigned to @clemenci

changed milestone to %v33r1

added lhcb-gaudi-head lhcb-run2-patches-dev4 labels

I'm pretty sure this is fine for Atlas (they have their own FindXYZ.cmake modules) and for LHCb master branch, but I'm not sure about LHCb run2-patches branch.

• [2020-03-21 00:08] Validation started with lhcb-gaudi-head#2561
• [2020-03-21 00:09] Validation started with lhcb-run2-patches-dev4#272
• [2020-03-22 00:04] Validation started with lhcb-gaudi-head#2562
• [2020-03-22 00:14] Validation started with lhcb-run2-patches-dev4#273
• [2020-03-23 00:07] Validation started with lhcb-gaudi-head#2563
• [2020-03-23 00:09] Validation started with lhcb-run2-patches-dev4#274

approved this merge request

unmarked as a Work In Progress

I'll fix run2-patches after the merge.

mentioned in commit 2c540929

merged

mentioned in merge request lhcb/Moore!432 (merged)