Auto merge of #628 - asomers:sysconf, r=alexcrichton

src/unix/bsd/freebsdlike/dragonfly/mod.rs

src/unix/bsd/freebsdlike/freebsd/mod.rs

src/unix/bsd/freebsdlike/mod.rs

src/unix/bsd/netbsdlike/mod.rs

src/unix/bsd/netbsdlike/netbsd/mod.rs

src/unix/bsd/netbsdlike/openbsdlike/mod.rs

src/unix/notbsd/android/mod.rs

src/unix/notbsd/linux/mips/mod.rs

src/unix/notbsd/linux/mod.rs

src/unix/notbsd/linux/other/mod.rs

src/unix/notbsd/linux/s390x.rs

src/unix/solaris/mod.rs