Is your feature request related to a problem? Please describe.
Building node for s390x requires libatomic as the comment in v8.gyp reports:

       # Platforms that don't have Compare-And-Swap support need to link atomic
       # library to implement atomic memory access

Describe the solution you'd like
s390x has many atomic instructions including a few compare-and-swap instructions (differing on operand size).

Describe alternatives you've considered
I am curious as to which atomic operations are required and where in the code they are. I would look at adding them to eliminate the need for libatomic.