de847765

By: Tom Sydney Kerckhove <syd@cs-syd.eu>

Fix race condition in mutation log output by using block buffering

Set stderr to BlockBuffering so each hPutStr call writes the full
multi-line mutation log entry as a single atomic syscall, preventing
interleaved output from concurrent mutation threads.

Also update the defaultSettings golden file with the two new settings
fields added in a previous commit.
forwardCompatibilitymutation-opt-env-confmutation-really-safe-moneymutation-releasemutation-safe-coloured-textmutation-sydtest-mutation-examplepre-commitreleaseshellconfiguredevShelldefaultx86_64-linux