ubuntu: bump gcc to 4.9 on 12.04

[targos]

The latest version of 4.8 available for 12.04 is 4.8.4.
It is not able to build V8 from version 5.7 and does not
satisfy the requirements to build Node.js.

Refs: nodejs/node#11840
Refs: nodejs/v8#5

/cc @nodejs/build @bnoordhuis @rvagg

[targos]

ping. I haven't tested either but I think it's important to test this (and update the machines) soon.
It is blocking nodejs/node#11752.

[jbergstroem]

Ah. Well, seeing how at least one other build member agrees I'll log in to one of our testers and replace it. Will update this issue.

[jbergstroem]

Edit: all three builders now runs gcc 4.9. Looks like there were symlinks missing for ccache so i fixed that as well. Please let me know how testing goes and if we need to do something else.

[targos]

I started a build with V8 5.7 and it's fully green on Linux: https://ci.nodejs.org/job/node-test-commit-linux/8603/

[targos]

This seems to cause a problem with clang 3.4.1. https://ci.nodejs.org/job/node-test-commit-linux/8680/nodes=ubuntu1204-clang341-64/

[bnoordhuis]

@targos The ubuntu1204-clang341-64 buildbot was taken out of commission. Does that mean this pull request can go through now?

[targos]

Yes, I think so.

[targos]

ping @nodejs/build

[gibfahn]

I'm okay with this landing, but we're trying to move to the scripts in ansible/, so this change probably needs to be made there as well.

[targos]

I can't find the place where Ubuntu 1204 is configured in ansible/

[gibfahn]

I can't find the place where Ubuntu 1204 is configured in ansible/

It might not have been added yet, I haven't had a chance to check out the new scripts, that's more a question for @jbergstroem @joaocgreis @piccoloaiutante

[piccoloaiutante]

@targos I think you could add a new section at the end of https://github.com/nodejs/build/blob/master/ansible/roles/baselayout/vars/main.yml like this:

ubuntu12: [
   'ccache',
   'gcc-4.9',
   'g++-4.9',
   'git',
]

is it correct @jbergstroem ?

[targos]

@piccoloaiutante OK thank you. I added it. Let me know if something else is missing.