sys::sendfile enable it on solaris based systems #128

Job	Run time
rust_stable	57s
linux_native_builds (x86_64-unknown-linux-gnu)	1m 2s
tier3 (x86_64-unknown-dragonfly)	51s
linux_native_builds (x86_64-unknown-linux-musl)	1m 1s
macos	1m 34s
tier3 (x86_64-unknown-openbsd)	52s
minver	13s
tier3 (armv7-unknown-linux-uclibceabihf)	23s
rustfmt	12s
tier3 (x86_64-unknown-haiku)	51s
cross (arm-unknown-linux-gnueabi)	1m 27s
redox	34s
cross (armv7-unknown-linux-gnueabihf)	1m 30s
cross_compiling (aarch64-linux-android)	33s
cross (i686-unknown-linux-gnu)	1m 40s
cross_compiling (arm-linux-androideabi)	29s
cross (i686-unknown-linux-musl)	1m 41s
cross_compiling (armv7-linux-androideabi)	34s
cross (mips-unknown-linux-gnu)	1m 31s
cross (mips64-unknown-linux-gnuabi64)	1m 35s
cross_compiling (i686-linux-android)	32s
cross (mips64el-unknown-linux-gnuabi64)	1m 30s
cross_compiling (x86_64-linux-android)	33s
cross (mipsel-unknown-linux-gnu)	1m 28s
cross_compiling (arm-unknown-linux-musleabi)	31s
cross (powerpc64le-unknown-linux-gnu)	1m 37s
cross_compiling (x86_64-unknown-fuchsia)	26s
cross_compiling (x86_64-unknown-illumos)	23s
cross_compiling (aarch64-apple-ios, true)	26s
cross_compiling (powerpc64-unknown-linux-gnu)	33s
cross_compiling (s390x-unknown-linux-gnu)	29s
cross_compiling (x86_64-unknown-linux-gnux32)	33s
cross_compiling (x86_64-unknown-netbsd)	26s
	28m 57s

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