Auto merge of #1576 - GrayJack:utmpx_netbsd, r=gnzlbg
Auto merge of #1576 - GrayJack:utmpx_netbsd, r=gnzlbg

Implement utmpx.h itens for NetBSD

This PR partially closes #1534

If add the constants, structs and and extra traid implmentation

rust-lang/libc,rust-lang/libc,rust-lang/libc