Add GNU/Hurd support #35

Job	Run time
rust_stable	1m 0s
minver	16s
linux_native_builds (x86_64-unknown-linux-gnu)	1m 41s
macos	1m 29s
linux_native_builds (x86_64-unknown-linux-musl)	1m 35s
rustfmt	13s
tier3 (x86_64-unknown-dragonfly)	1m 19s
tier3 (x86_64-unknown-openbsd)	52s
tier3 (armv7-unknown-linux-uclibceabihf)	1m 42s
tier3 (x86_64-unknown-haiku)	52s
tier3 (i686-unknown-hurd-gnu)	31s
redox	34s
cross (arm-unknown-linux-gnueabi)	1m 34s
cross_compiling (aarch64-linux-android)	42s
cross_compiling (arm-linux-androideabi)	33s
cross (armv7-unknown-linux-gnueabihf)	2m 37s
cross_compiling (armv7-linux-androideabi)	49s
cross (i686-unknown-linux-gnu)	1m 26s
cross_compiling (i686-linux-android)	32s
cross (i686-unknown-linux-musl)	2m 28s
cross_compiling (x86_64-linux-android)	48s
cross (mips-unknown-linux-gnu)	2m 15s
cross_compiling (arm-unknown-linux-musleabi)	56s
cross (mips64-unknown-linux-gnuabi64)	1m 29s
cross_compiling (x86_64-unknown-fuchsia)	41s
cross (mips64el-unknown-linux-gnuabi64)	1m 39s
cross_compiling (x86_64-unknown-illumos)	25s
cross (mipsel-unknown-linux-gnu)	1m 27s
cross_compiling (aarch64-apple-ios, true)	39s
cross (powerpc64le-unknown-linux-gnu)	1m 28s
cross_compiling (powerpc64-unknown-linux-gnu)	30s
cross_compiling (s390x-unknown-linux-gnu)	34s
cross_compiling (x86_64-unknown-linux-gnux32)	49s
cross_compiling (x86_64-unknown-netbsd)	32s
	36m 57s

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