Travis CI environment change breaks clang builds
It looks like an unannounced environment change in Travis CI's workers prevents LeakSanitizer from working correctly, breaking our Travis builds on clang. This seems to disable ptrace capabilities, which for some reason LeakSanitizer needs to run properly on our forking tests. (See https://github.com/travis-ci/travis-ci/issues/9033).
We can hope they fix this soon, or we can try to work around it by changing our
.travis.yml to use a sudo-enabled build environment. (This has the drawback that some of our tests depend on running as non-root, but I think they all get skipped if running as root.)