Merge branch 'socketpair' into 'master'

src/c_vec.rs

src/header/_aio/cbindgen.toml

src/header/_fenv/cbindgen.toml

src/header/_template/cbindgen.toml

src/header/_wctype/cbindgen.toml

src/header/assert/cbindgen.toml

src/header/ctype/cbindgen.toml

src/header/dirent/cbindgen.toml

src/header/dlfcn/cbindgen.toml

src/header/errno/cbindgen.toml

src/header/fcntl/cbindgen.toml

src/header/float/cbindgen.toml

src/header/fnmatch/cbindgen.toml

src/header/getopt/cbindgen.toml

src/header/grp/cbindgen.toml

src/header/inttypes/cbindgen.toml

src/header/libgen/cbindgen.toml

src/header/limits/cbindgen.toml

src/header/locale/cbindgen.toml

src/header/netdb/cbindgen.toml