As of #587 the asan build fails when -fundefined is passed with the following error:

ld.lld: error: undefined symbol: __muloti4

This seems related to envoyproxy/envoy#13973, which was introduced via an update to
absl, and eventually was resolved in Envoy by bumping absl. Yet this error persist in Nighthawk.

I've spend some time trying to figure out how to address this, without coming up with a good solution yet.
To unblock, -fundefined gets dropped from .bazelrc in #587.

Filing this issue to track status of re-enabling -fundefined