Add flag Wheader-hygiene to warn about usage of namespace directive in global context in header
Add flag Wheader-hygiene to warn about usage of namespace directive in global context in header

petricm/LCIO,petricm/LCIO,petricm/LCIO,iLCSoft/LCIO,iLCSoft/LCIO,petricm/LCIO,petricm/LCIO,iLCSoft/LCIO,iLCSoft/LCIO,iLCSoft/LCIO,iLCSoft/LCIO,petricm/LCIO