attempt to fix travis bug on large stdout/stderr dumps

.travis.yml

@@ -40,6 +40,9 @@ before_script:
 script:
    # make release packages
  - fakeroot ./packaging/git-build
+   # Make sure stdout is in blocking mode. If we don't, then conda create will barf during downloads.
+   # See https://github.com/travis-ci/travis-ci/issues/4704#issuecomment-348435959 for details.
+ - python -c 'import os,sys,fcntl; flags = fcntl.fcntl(sys.stdout, fcntl.F_GETFL); fcntl.fcntl(sys.stdout, fcntl.F_SETFL, flags&~os.O_NONBLOCK);'
    # make self-extractor
  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then ./makeself/build-x86_64-static.sh; fi
    # test build and installer