$ mir_demo_server --arw-file

[2017-03-21 14:03:57.709154] mirserver: Starting
[2017-03-21 14:03:57.709255] mircommon: Loading modules from: /usr/lib/x86_64-linux-gnu/mir/server-platform
[2017-03-21 14:03:57.709295] mircommon: Loading module: /usr/lib/x86_64-linux-gnu/mir/server-platform/server-mesa-x11.so.11
ERROR: Cannot create report: [Errno 17] File exists: '/var/crash/_usr_bin_mir_demo_server.1000.crash'
ERROR: /build/mir-sajBv9/mir-0.26.1+16.04.20170209.1/src/server/graphics/default_configuration.cpp(133): Throw in function mir::DefaultServerConfiguration::the_graphics_platform()::<lambda()>
Dynamic exception type: boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<std::runtime_error> >
std::exception::what: Exception while creating graphics platform
ERROR: /build/mir-sajBv9/mir-0.26.1+16.04.20170209.1/src/platform/graphics/platform_probe.cpp(63): Throw in function std::shared_ptr<mir::SharedLibrary> mir::graphics::module_for_device(const std::vector<std::shared_ptr<mir::SharedLibrary> >&, const mir::options::ProgramOption&)
Dynamic exception type: boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<std::runtime_error> >
std::exception::what: Failed to find platform for current system