Merge remote-tracking branch 'tor-github/pr/1094' into maint-0.3.5

diff --cc .travis.yml
index 3c0a3a02a819eaf808e332d04e9b96c380ca458f,a1a48baffef18c318788d4757c1fcfdf34029b48..861b37f085bcfd1a0fdadde16f918e8913a0280e
--- 1/.travis.yml
--- 2/.travis.yml
+++ b/.travis.yml
@@@ -70,7 -70,17 +70,11 @@@ matrix
    ## Careful! We use global envs, which makes it hard to exclude or
    ## allow failures by env:
    ## https://docs.travis-ci.com/user/customizing-the-build#matching-jobs-with-allow_failures
+   allow_failures:
+     ## test-stem sometimes hangs on Travis
+     - env: TEST_STEM="yes"
+ 
    exclude:
 -    ## Clang doesn't work in containerized builds, see below.
 -    - compiler: clang
 -      sudo: false
 -    ## Non-containerized gcc are slow and redundant.
 -    - compiler: gcc
 -      sudo: required
      ## gcc on OSX is less useful, because the default compiler is clang.
      - compiler: gcc
        os: osx