Use -Wno-gnu-zero-variadic-macro-arguments more

Summary:
Add it to KDECompilerSettings.cmake instead of
KDEFrameworkCompilerSettings.cmake.

Users can then just enable -pedantic without worrying about the
gnu-zero-variadic-macro-arguments warning.

This fixes some warnings in e.g. kdenlive

Reviewers: kossebau, apol, dfaure

Reviewed By: apol

Subscribers: apol, Frameworks, Build System

Tags: Frameworks, Build System

Differential Revision: https://phabricator.kde.org/D5302