[build] Add -fsanitize=undefined to debug flags (#608)
[build] Add -fsanitize=undefined to debug flags (#608)


koreader/koreader-base,NiLuJe/koreader-base,koreader/koreader-base,houqp/koreader-base,NiLuJe/koreader-base,Frenzie/koreader-base,NiLuJe/koreader-base,Frenzie/koreader-base,koreader/koreader-base,NiLuJe/koreader-base,Frenzie/koreader-base,houqp/koreader-base,koreader/koreader-base,houqp/koreader-base,houqp/koreader-base,Frenzie/koreader-base