LONG, long time ago, when he was a wee lad in St. Louis, Al Hirschfeld wanted to be a sculptor. In a way, that's what he became.
"A sculpture," said Hirschfeld, "is really a drawing you fall over in the dark."
Al Hirschfeld is probably the best-known "drawer" in the world. His show-business caricatures appear every Sunday in The New York Times Arts and Leisure section, often on the front page, and his sprightly portraits of famous actors and actresses have been reproduced millions of times in recent years on U.S. postage stamps. Hirschfeld, who is 93 years old and shows no signs of slowing down, will make a rare return visit to his hometown of St. Louis this …