Import Upstream version 20180207
- [DBH] basis-library/posix/error.sig
- [DBH] basis-library/posix/error.sml
- [DBH] basis-library/posix/file-sys.sig
- [DBH] basis-library/posix/file-sys.sml
- [DBH] basis-library/posix/flags.sig
- [DBH] basis-library/posix/flags.sml
- [DBH] basis-library/posix/io.sig
- [DBH] basis-library/posix/io.sml
- [DBH] basis-library/posix/posix.sig
- [DBH] basis-library/posix/posix.sml
- [DBH] basis-library/posix/pre-posix.sml
- [DBH] basis-library/posix/proc-env.sig
- [DBH] basis-library/posix/proc-env.sml
- [DBH] basis-library/posix/process.sig
- [DBH] basis-library/posix/process.sml
- [DBH] basis-library/posix/signal.sig
- [DBH] basis-library/posix/signal.sml
- [DBH] basis-library/posix/stub-mingw.sml
- [DBH] basis-library/posix/sys-db.sig
- [DBH] basis-library/posix/sys-db.sml
- [DBH] basis-library/posix/tty.sig
- [DBH] basis-library/posix/tty.sml