Try to avoid panicking in PosixParser if there's no /dev/tty

[abrander]

When using go-prompt before /dev/ is populated, it will panic() from
NewStandardInputParser() because /dev/ isn't populated yet.

This will use stdin (file descriptor 0) as a fallback if /dev/tty doesn't exist.

Furthermore GetWinSize() will return the default console size if the
ioctl() call fails. This can happen if the default stdin is not a
terminal, but a pipe as fixed in commit 846777c and described in
issue #88.

[abrander]

This will enable us to close the following issues if merged:

#39 runtime error : integer divided by zero. Facing this issue when I am trying to run go-prompt as a docker container
#71 Panic while debugging using VSCODE linux
#154 [Bug] When starting docker image with CMD it panics

[pgollangi]

@abrander @c-bata any updates on this?

[trantaiBD]

hi @c-bata when this MR could be merged? Thanks!

[Verseth]

@trantaiBD Unfortunately no one has been maintaining it for the last 2/3 years.

I've created a fork and merged lots of PRs from this repo.
I've addressed this issue and merged this PR in my fork: elk-language#8.

There's lots of new functionalities like customisable syntax highlighting, multiline editing, customisable automatic indentation.

I use it to build a REPL for my programming language, but I want to maintain it as an independent library.

https://github.com/elk-language/go-prompt