bug#32279: activate-readline interaction with git

[Jelle Licht]

Loading the (git) module after a call to (activate-readline) from
(ice-9 readline) stalls my repl, in most (9 out of 10) cases.

Observe:

--8<---------------cut here---------------start------------->8---
$ guile -q
GNU Guile 2.2.4
Copyright (C) 1995-2017 Free Software Foundation, Inc.

Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.

Enter `,help' for help.
scheme@(guile-user)> (use-modules (ice-9 readline))
scheme@(guile-user)> (activate-readline)
scheme@(guile-user)> (use-modules (git)) (display "This still shows up?")
This still shows up?
;; <- It is stuck here, not even a SIGINT works
[1]+  Stopped                 guile -q
--8<---------------cut here---------------end--------------->8---

I have verified that using guile without any repl does not exhibit this
behaviour. I have attached the `strace -f guile' where I
pipe the offending code into stdin, and then the problem does not seem
to present itself. See "working.log".

I have also attached the strace of the repl when it exhibits the issue;
see "broken.log".

I think this might be related to
http://lists.gnu.org/archive/html/bug-guix/2018-07/msg00170.html as well.

working.log
Description: Text document

broken.log
Description: Text document