Fixes <https://issues.guix.gnu.org/57827>.
Reported by Mathieu Othacehe <othacehe@gnu.org>.
Fixes a regression introduced with the Shepherd 0.9.2 upgrade in
1ba0e38267c9ff8bb476285091be6e297bbf136e, whereby IN and OUT would no
longer be closed when 'fork+exec-command/container' would call
'exec-command*' as part of the THUNK passed to 'container-excursion*'.
This is because the Shepherd 0.9.2 assumes file descriptors are properly
marked as O_CLOEXEC and, consequently, 'exec-command' no longer run the
close(2) loop prior to 'exec'.
* gnu/build/linux-container.scm (container-excursion*): Add calls to
'fcntl'.
6abdcef4a6