Merge remote-tracking branch 'tor-github/pr/1094' into maint-0.4.0

diff --cc .travis.yml
index 30e6d9a6b5fe28ca3da6c194dd717d71ebd83524,a1a48baffef18c318788d4757c1fcfdf34029b48..7d8877c2acf0f0357f34ee11f7cf3f91d106afba
--- 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