fish shell config issue starting 3.6.4 package

[Xavier Delaruelle]

Hello,

Since fish shell has been updated to 3.6.4 at the beginning of the year, I
obtain a configuration error:

    fish: Unknown command: pgrep
    /etc/fish/conf.d/01_fish_variables.fish (line 13):
            pgrep fish | grep -v \^$fish_pid\$ | xargs -r kill
            ^~~~^
    from sourcing file /etc/fish/conf.d/01_fish_variables.fish
        called on line 248 of file /usr/share/fish/config.fish
    from sourcing file /usr/share/fish/config.fish
        called during startup

It seems like default fish configuration relies on pgrep which is not found
on Cygwin.

Same issue occurs also with 3.7.0.

Regards,
Xavier