Auto merge of #1399 - josephlr:getrandom, r=gnzlbg

src/unix/linux_like/linux/gnu/mod.rs

src/unix/linux_like/linux/musl/b32/arm.rs

src/unix/linux_like/linux/musl/b32/powerpc.rs

src/unix/linux_like/linux/musl/b32/x86.rs

src/unix/linux_like/linux/musl/b64/mod.rs