'linux' is not usable as identifier, because C compilers targeting
Linux predefine it as a macro expanding to 1.  Add it to
@polluted_words. 'unix' is already there.

Suggested-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Message-Id: <20220707005602.696557-2-pizhenwei@bytedance.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Konstantin Kostiuk <kkostiuk@redhat.com>