Add -Wnon-virtual-dtor to GCC build
Add -Wnon-virtual-dtor to GCC build

GH #382

webmaster128/botan,webmaster128/botan,Rohde-Schwarz-Cybersecurity/botan,randombit/botan,webmaster128/botan,webmaster128/botan,webmaster128/botan,randombit/botan,randombit/botan,Rohde-Schwarz-Cybersecurity/botan,Rohde-Schwarz-Cybersecurity/botan,Rohde-Schwarz-Cybersecurity/botan,Rohde-Schwarz-Cybersecurity/botan,randombit/botan,randombit/botan,Rohde-Schwarz-Cybersecurity/botan