Merge topic 'relative-paths'

8526756b61 cmOutputConverter: Adopt relative path conversion helpers
013ec595c8 cmLocalGenerator: De-duplicate StateSnapshot member
24bfdbcffb cmLocalGenerator: Remove unused MaybeRelativeToCurSrcDir method
d6fe1bdb6d cmLocalGenerator: Localize logic mapping source path to object file name
4cb6a53bf5 cmListFileCache: Simplify relative path conversion in backtraces
5b3a71a83f cmSystemTools: Adopt RelativeIfUnder helper
ea9b1d36b8 cmStateDirectory: Clarify relative path top selection logic
2d9109df7c cmStateDirectory: Remove network path logic from relative path top selection
...

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !6128