x/sys/unix: termios.h CRTSCTS flag missing from UNIX syscall package

[gopherbot]

by smith.winston.101:

Go version 1.3.1.

The syscall package includes a number of constants from termios.h to allow for terminal
handling without needing to use cgo.  For example, see the definitions syscall.CLOCAL
et. al. from types_linux.go (interestingly, some of these definitions for other UNIXes
can be found in zerrors_*_*.go files).

However, the CRTSCTS flag is missing.  It's definition (from linux/termios.h) is a
follows:

# define CRTSCTS  020000000000

This flag is used in the struct termios.c_cflag to indicate that RTS/CTS flow control
should be used.  While it's not part of POSIX, it's present on Linux, Mac OS X, BSD.

Without this definition in the syscall package, hardware flow control can only be enable
via CGO which prohibits cross compilation (unless the constant is hardcoded!).

NOTE: There are a number of other termios related functions such as cfmakeraw() and
isatty() that are also missing from the syscall package.

[ianlancetaylor]

Comment 1:

New additions to the syscall package are now being done in the go.sys package instead
(https://docs.google.com/a/golang.org/document/d/1QXzI9I1pOfZPujQzxhyRy6EeHYTQitKKjHfpq0zpxZs/edit).
 Redirecting this issue accordingly.

Labels changed: added repo-sys, release-none.

[safetydank]

This constant appears to be in package "unix"

[ianlancetaylor]

Looks like it's currently there for GNU/Linux, but not yet for any other OS.

[gopherbot]

Change https://golang.org/cl/103355 mentions this issue: unix: add CRTSCTS on netbsd and openbsd