Log Message:
znc: Update to 1.7.5.

pkgsrc changes:

- Switched to cmake.

Upstream changes:

- modpython: Add support for Python 3.8
- modtcl: install .tcl files when building with CMake
- nickserv: report success of Clear commands
- Update translations, add Italian, Bulgarian, fix name of Dutch
- Update error messages to be clearer
- Add a deprecation warning to ./configure to use CMake instead in addition to \ 
an already existing warning in README