Minor compiler warning cleanup
- gitlab CI: stop requiring
Signed-off-byin commits - Handle
-Wunused-const-variablewarnings - Handle
-Wdiscarded-qualifierswarnings - Handle
-Wempty-bodywarnings
Signed-off-by in commits-Wunused-const-variable warnings-Wdiscarded-qualifiers warnings-Wempty-body warnings