Fix compiler warnings in auto-generated mkclass code.

Refs #5349
Fix compiler warnings in ThreadPool::ThreadPool.

Refs #5349
Fix compiler warnings in ScheduledDowntime::FindNextSegment.

Refs #5349
Fix compiler warning in CompatUtility::GetServiceNotificationNotificationOptions.

Refs #5349
Fix compiler warnings in the CompatLogger class.

Refs #5349
Fix compiler warnings in Service::ProcessCheckResult.

Refs #5349
Merge branch 'feature/compiler-warnings-5349' into next

Fixes #5349