This commit adds support for AIX operating system.
- move term_solaris.go to term_nosyscall6.go. AIX like solaris doesn't
provide syscall.Syscall6 and must rely on x/sys/unix in order to perform
syscalls.
- This patch won't work with versions prior to 1.13 because it needs
some constants added by https://go-review.googlesource.com/c/go/+/171339.
* Add support for solaris
* Change state to handle system dependent termios type.
* Move syscalls to get and set termios to functions in files only built
for respective platforms.
* Create `term_unix.go` go file built on all supported unices except
solaris with types and functions valid for all of them.
* Change `MakeRaw` to set VMIN and VTIME to default values.
Fixes#95.
* Fix error handling
Doing the string comparison could be improved, but at least we should
return an error, if it is not "errno 0".