doc: upgrade Clang requirement to 3.4.2

[targos]

Clang 3.4.1 has a bug that prevents compilation of V8.
As of Node.js 8.0.0 we stopped floating a workaround for this issue.

I don't have a test system to check if 3.4.2 is enough.

/cc @nodejs/build

Checklist

• documentation is changed or added
• commit message follows commit guidelines

[bnoordhuis]

LGTM and good catch on configure.

I'd be okay with raising the baseline to 3.5.2 or 3.6.2 for node 8. We'll be supporting it until 2021, it would make sense to start with a compiler that's not already long in the tooth.

[mhdawson]

In terms 3.5.2 and 3.6.2 will those run on the existing OS levels were Clang is used in our regression runs ?

[jbergstroem]

I'm all for raising the bar in node 8 as well. ubuntu trusty seems to offer clang 3.4, 3.5, 3.6 and 3.8.

Any arguments on 3.5.x vs 3.6.x?

[benjamingr]

LGTM

[bnoordhuis]

In terms 3.5.2 and 3.6.2 will those run on the existing OS levels were Clang is used in our regression runs ?

I'd say so. I don't think we have any systems in our matrix where you can install 3.4 but not 3.5 or 3.6.

Any arguments on 3.5.x vs 3.6.x?

PPC support got a big boost in 3.6. Might be worth it for that reason alone.

[jbergstroem]

@bnoordhuis said:
PPC support got a big boost in 3.6. Might be worth it for that reason alone.

Sounds good to me. The newer, the better.

[jasnell]

CI since there's a change in the configure script here: https://ci.nodejs.org/job/node-test-pull-request/7489/

[jasnell]

CI failure is unrelated

[mhdawson]

LGTM

[jasnell]

Landed in b4f59a7

[gibfahn]

I'm assuming this doesn't apply to v7 and earlier, LMK if that's not correct.

[bnoordhuis]

We carry a compatibility patch in older branches although it's no longer tested now that the clang 3.4.1 buildbot has been decommissioned. I'd back-port this PR, that way people know what the known-good version of clang is.

[gibfahn]

Backported in 11a7875