Use devtoolset-6 for s390x on node gt 11.x

[sam-github]

Depends on #1755

[sam-github]

devtoolset-6 is authorized for use on IBM systems (and the s390x boxes are IBM systems) for the purposes Node.js would use it for, but installing it requires downloading RPMs through an authenticated portal. I don't see how this can be ansibled, so I created /data/devtoolset-6-s390x-rpms/ on the 3 s390x boxes. I installed it on only -3, using yum install /data/devtoolset-6-s390x-rpms/*.rpm. I haven't done this on the other 2 yet. Or added docs to the README on this manual setup task.

/to @mhdawson

[sam-github]

It appears to me that devtoolset does indeed build more portable binaries, even with no additional configuration. See:

[root@test-linuxonecc-rhel72-s390x-3 data]# docker run --rm -it -v /home/iojs/sam-github:/sam-github rhel:7.6 /sam-github/node-gcc -p process.versions
/sam-github/node-gcc: /lib64/libstdc++.so.6: version `GLIBCXX_3.4.20' not found (required by /sam-github/node-gcc)
[root@test-linuxonecc-rhel72-s390x-3 data]# docker run --rm -it -v /home/iojs/sam-github:/sam-github rhel:7.5 /sam-github/node-devtools -p process.versions
{ node: '12.0.0-pre',
  v8: '7.4.288.18-node.16',
  uv: '1.27.0',
  zlib: '1.2.11',
  brotli: '1.0.7',
  ares: '1.15.0',
  modules: '72',
  nghttp2: '1.37.0',
  napi: '4',
  llhttp: '1.1.1',
  http_parser: '2.8.0',
  openssl: '1.1.1b',
  cldr: '34.0',
  icu: '63.1',
  tz: '2018e',
  unicode: '11.0' }
[root@test-linuxonecc-rhel72-s390x-3 data]# cat /etc/redhat-release 
Red Hat Enterprise Linux Server release 7.6 (Maipo)

[mhdawson]

We might want to leave this PR with the selection being gcc6, until we get the ansible changes in to help install the dev toolset as well?

EDIT: Nevermind, my confusion. There is a separate PR for gcc6 and this one is focused on the dev toolset.

[mhdawson]

We've discussed this approach for the dev toolset. Store the rpms on one of the s390 machines and then have ansible pull/install from there when it is run. This is because we believe the licence allows them to be on IBM machines (which the ones in the community are) but not otherwise redistributed. This approach is not perfect but a step better than simply manually installing on all machines.

[mhdawson]

LGTM

[mhdawson]

Landed as cf02bff