Log Message:
logswan: update to 2.1.9.

Logswan 2.1.9 (2021-02-15)

- Stop forcing FORTIFY_SOURCE=2, it should be package builders decision
- Add link to Homebrew package in the README
- Remove unused countryId variable
- Remove dead increments for argc and argv
- Rename variables to get rid of all camelCase occurences
- Remove the measuring Logswan memory usage section from the README
- Try to harmonize usage information everywhere
- Rename the displayUsage() function to usage()
- Rename all the parse*() functions to use snake_case
- Get rid of global variables, move all declarations to main()