find-lang.sh syntax

[Tanguy Eric <eric tanguy univ-nantes fr>]

In a spec file i found :
%find_lang %{name} --all-name which is translated
to /usr/lib/rpm/redhat/find-lang.sh %{buildroot} %{name} --all-name but
during the build process i obtain this error message : 
+ /usr/lib/rpm/redhat/find-lang.sh /var/tmp/ruby-gettext-1.0.0-2.rcn.FC6-root ruby-gettext --all-name
grep: unrecognized option `--all-name'
Usage: grep [OPTION]... PATTERN [FILE]...
Try `grep --help' for more information.
No translations found for ruby-gettext
in /var/tmp/ruby-gettext-1.0.0-2.rcn.FC6-root

it seems that --all-name is an unrecognized option but looking inside
the script it's a valid option but maybe i don't understand or use it
well.
Someone could help me ?

Eric