Merge remote-tracking branch 'tor-github/pr/990' into maint-0.3.5

    - RUST_OPTIONS="--enable-rust" TOR_RUST_DEPENDENCIES=true

matrix:

  ## include creates builds with gcc, linux, sudo: false

  ## include creates builds with gcc, linux

  include:

    ## We include a single coverage build with the best options for coverage

    - env: COVERAGE_OPTIONS="--enable-coverage" HARDENING_OPTIONS=""

  ## allow failures by env:

  ## https://docs.travis-ci.com/user/customizing-the-build#matching-jobs-with-allow_failures

  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

      ## TOR_RUST_DEPENDENCIES is spelt RUST_DEPENDENCIES in 0.3.2

      env: RUST_OPTIONS="--enable-rust" TOR_RUST_DEPENDENCIES=true HARDENING_OPTIONS=""

## We don't need sudo. (The "apt:" stanza after this allows us to not need

## sudo; otherwise, we would need it for getting dependencies.)

##

## But we use "sudo: required" to force non-containerized builds, working

## around a Travis CI environment issue: clang LeakAnalyzer fails

## because it requires ptrace and the containerized environment no

## longer allows ptrace.

## https://github.com/travis-ci/travis-ci/issues/9033

##

## In the matrix above, we exclude redundant combinations.

sudo:

  - false

  - required

## (Linux only) Use the latest Linux image (Ubuntu Trusty)

dist: trusty

  o Minor features (continuous integration):

    - Remove sudo configuration lines from .travis.yml as they are no longer

      needed with current Travis build environment. Resolves issue 30213.