bug#28034: elixir build fails

[nee]

Hello, thank you for the fast and detailed reply.
I made two patches that upgrade erlang and elixir and disable the
failing tests in elixir, and got it to build again.


I sometimes get this undeterministic compile error (see the attached
log). It's always the same error, but it doesn't appear every time, so I
can get a passing build running:

`until ./pre-inst-env guix build elixir; do sleep 1; done`

I don't think that it is related to the version upgrade because I also
got this with the old versions when I first tried to build it today.


While this still not good, it is at least an improvement over the
current state where the package will fail to install in 100% of cases.

0001-gnu-erlang-Update-to-20.1.patch
Description: Text Data

0002-gnu-elixir-Update-to-1.5.2-and-disable-failing-tests.patch
Description: Text Data

elixir-epipe-error.log
Description: Text Data