NEW YORK — The mackintosh might be 150 years old, but it got new life on the spring runways last month. The simple, single-breasted style, which traces its roots to 19th-century Scotland, was the key outerwear trend to emerge. And with rainwear makers anticipating a strong season, this should be a hot seller across all price points. Here, one of the best macks of the season, from Michael Kors.