Revert "#4273 "clean" exit -> crash"

This reverts commit 5cba99d4e7ddb0ed34cc7345e9684e9b70c911f6.
fix SIGFPE in LuaParser (#4274)
fix hard exit in luaL_optFoo() when used outside out a lua_pcall (#4273)
fix gcc warning about unused LOG_SECTION_COMPARE
make CVertexArray safe against repeated destruction