damnms:

i use fedora 34, installed the required software and "which" is available on the command line

[oli@lucy openwrt]$ which which | grep which
which ()
eval ${which_declare} ) | /usr/bin/which --tty-only --read-alias --read-functions --show-tilde --show-dot "$@"

but when i run "./scripts/feeds update -a" i get:
hecking 'perl'... ok.
Checking 'python2-cleanup'... ok.
Checking 'python'... ok.
Checking 'python3'... ok.
Checking 'git'... ok.
Checking 'file'... ok.
Checking 'rsync'... ok.
Checking 'which'... failed.
Checking 'ldconfig-stub'... ok.

Build dependency: Please install 'which'

Prerequisite check failed. Use FORCE=1 to override.
gmake: *** [/home/oli/openwrt/include/toplevel.mk:180: staging_dir/host/.prereq-build] Fehler 1