InstallRequiredSystemLibraries: Allow repeat use per-config

To be able to include InstallRequiredSystemLibraries more than once
(e.g. to get the Debug and Release libraries separately), clear the
internal library list for non-matching configuration.
Merge topic 'InstallRequiredSystemLibraries-repeat' into next

15a19c31 InstallRequiredSystemLibraries: Allow repeat use per-config