‘please migrate to using O_CLOEXEC instead’
Just so happened to be running with debug messages on, and noticed this coming from GLib:
g_unix_open_pipe() called with FD_CLOEXEC; please migrate to using O_CLOEXEC instead
The comment in GLib is:
* As of GLib 2.78, it is preferred to pass `O_CLOEXEC` in, rather than
* `FD_CLOEXEC`, as that matches the underlying `pipe()` API more closely. Prior
* to 2.78, only `FD_CLOEXEC` was supported. Support for `FD_CLOEXEC` may be
* deprecated and removed in future.