After backing off a self-imposed deadline several weeks ago, US President Donald Trump has said that Canada must sign a deal with the US and Mexico by September 30.Canada and the United States showed scant sign of being close to striking a deal on revamping the trilateral NAFTA that underpins $1.2 trillion in annual trade , as Canadian sources played down talk of a US quota on autos.While multiple deadlines have been and gone during the more than year-long negotiations to renew NAFTA, pressure on Canada to agree to a deal is growing . . .