message: _build: macos: enable UBSAN
diff: @@ -34,9 +34,8 @@ with drake.Drake('../..') as d:
  os.environ['MACOSX_DEPLOYMENT_TARGET'] = '10.7' # ensure that build is compatible with 10.7
  cxx_config = drake.cxx.Config()
  -
  - # XXX[still required but it shouldn't be the case]
  - cxx_config.flag('-stdlib=libc++')
  + cxx_config.flag('-stdlib=libc++') # XXX[still required but it shouldn't be the case]
  + cxx_config.flag('-fsanitize=undefined')
  d.run(cxx_toolkit,
  None,
  