Build

Add README #9

Job	Run time
Cross build (i686-w64-mingw32)	2m 45s
Cross build (aarch64-w64-mingw32)	53s
Cross build (armv7-unknown-linux-musleabihf)	1m 15s
Cross build (arm-unknown-linux-gnueabihf)	1m 50s
Cross build (i386-unknown-netbsdelf)	1m 52s
Cross build (aarch64-unknown-linux-android)	3m 58s
Cross build (aarch64-unknown-linux-musl)	1m 12s
Cross build (mipsel-unknown-linux-android21)	40s
Cross build (riscv64-unknown-linux-android)	50s
Cross build (arm-unknown-linux-gnueabi)	1m 38s
Cross build (aarch64-unknown-freebsd)	3m 58s
Cross build (armv6-unknown-linux-musleabihf)	1m 10s
Cross build (mips64el-unknown-linux-android)	44s
Cross build (x86_64-unknown-linux-musl)	1m 15s
Cross build (x86_64-w64-mingw32)	1m 1s
Cross build (x86_64-unknown-apple-darwin)	1m 11s
Cross build (i386-unknown-freebsd)	3m 26s
Cross build (armv7-unknown-linux-androideabi21)	3m 0s
Cross build (i386-unknown-linux-gnu)	1m 43s
Cross build (aarch64-unknown-linux-gnu)	1m 44s
Cross build (aarch64-unknown-apple-darwin)	1m 1s
Cross build (x86_64-unknown-linux-android)	2m 36s
Cross build (i686-unknown-linux-android21)	2m 23s
Cross build (x86_64-unknown-linux-gnu)	1m 38s
Cross build (x86_64-unknown-netbsd)	1m 48s
Cross build (x86_64-unknown-freebsd)	2m 8s
Cross build (i386-unknown-linux-musl)	58s
Cross build (x86_64-unknown-dragonfly)	2m 8s
	50m 45s

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