This example missed the fixes from commit 69b1bb49ed82
("examples: hide error for missing pkg-config path flag") and
commit 12a652a02b08 ("examples: fix build with old pkg-config").
Fixes: 08bd1a174461 ("examples/l3fwd-graph: add graph-based l3fwd skeleton")
Cc: stable@dpdk.org
Signed-off-by: David Marchand <david.marchand@redhat.com>