Allow OSX failures on Travis CI

[Sija]

Refs #3721 and #4494 (comment).

[matiasgarciaisaia]

There are two main reasons to not merge this by now.

1. We're testing if the CircleCI plan's limits are enough for us. There's a "build minutes per month" limit that we still don't know if are enough for us or not.
2. We're working with TravisCI (really awesome) support to learn why the Xcode 8.2 builds are randomly failing while trying to brew install llvm. I'm in contact with them, and hopefully will have an answer soon.

So I say we should wait 👍

[matiasgarciaisaia]

On second thought - we should allow failures for xcode 8.2 until it gets fixed.

[Sija]

Builds #8674, #8678 and #8746 failed on osx too.

[Sija]

We could add all osx section to allow_failures for now...

[matiasgarciaisaia]

Be my guest:

diff --git a/.travis.yml b/.travis.yml
index 55502d412..99495506c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,6 +3,7 @@ sudo: required
 dist: trusty
 services:
   - docker
+os: # need to declare on top level for `allow_failures` to work
 matrix:
   include:
     - env: ARCH=i386 ARCH_CMD=linux32
@@ -12,6 +13,8 @@ matrix:
     - os: osx
     - os: osx
       osx_image: xcode8.2
+  allow_failures:
+    - os: osx
   fast_finish: true
 before_install:
   - bin/ci prepare_system

[Sija]

I'm wondering is os the proper top-level key? Travis CI documentation mentions env key, but no os. Am I missing sth?

[Sija]

@matiasgarciaisaia I've pushed changes moving osx builds into allowed_failures section which seems to work (without adding os top-level key you suggested).

[Sija]

ping?

[sdogruyol]

Is there any blocker for this to be merged? @matiasgarciaisaia

[matiasgarciaisaia]

👍 LGTM. Thanks for the PR!