Three weeks after a building collapse in Bangladesh that killed more than 1,100 workers, the retailing giant H&M — the largest purchaser of garments from that country — agreed on Monday to sign a far-reaching and legally binding plan that requires retailers to help finance fire safety and building improvements in the factories they use in Bangladesh...Minutes after H&M announced its move, Inditex, a large Spanish apparel company best known for its Zara brand and stores, also agreed to sign onto the safety plan, labor groups said.