Auto merge of #720 - Susurrus:fcntl, r=alexcrichton

.travis.yml

Cargo.lock

README.md

appveyor.yml

ci/docker/aarch64-linux-android/Dockerfile

ci/docker/aarch64-unknown-linux-gnu/Dockerfile

ci/docker/arm-linux-androideabi/Dockerfile

ci/docker/arm-unknown-linux-gnueabihf/Dockerfile

ci/docker/i686-linux-android/Dockerfile

ci/docker/mips-unknown-linux-gnu/Dockerfile

ci/docker/mips-unknown-linux-musl/Dockerfile

ci/docker/mips64-unknown-linux-gnuabi64/Dockerfile

ci/docker/mipsel-unknown-linux-musl/Dockerfile

ci/docker/powerpc-unknown-linux-gnu/Dockerfile

ci/docker/powerpc64-unknown-linux-gnu/Dockerfile

ci/docker/s390x-unknown-linux-gnu/Dockerfile

ci/docker/x86_64-rumprun-netbsd/Dockerfile

ci/docker/x86_64-rumprun-netbsd/runtest.rs

ci/run-docker.sh

ci/run.sh