build: fix error when running `configure --disable-doc`

Signed-off-by: Thomas Haller <thaller@redhat.com>
route: fix return value of nl_rtgen_request()

According to documentation, nl_rtgen_request() returns 0 on success,
but before it returned the number of bytes sent.

Signed-off-by: Thomas Haller <thaller@redhat.com>
remove the obsolete src/cls directory

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Thomas Haller <thaller@redhat.com>
remove nl_cache_lookup() from cache.h

It is never defined.

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Thomas Haller <thaller@redhat.com>