After applying the patch from #177 to fix linking on NetBSD, I see:

Running s2n_malformed_handshake_test.c ... FAILED test 8
!((s2n_errno) == (0)) is not true (s2n_malformed_handshake_test.c line 270)
Error Message: 'no error'
Makefile:36: recipe for target 's2n_malformed_handshake_test' failed