Lincoln Logs are among a handful of classic toys made in the USA with American trees, but that’s likely to change in a matter of weeks. Pride Manufacturing — the Maine factory that makes Lincoln Logs and other wood products — is closing in April after losing its biggest contract, to make cigar tips for another company, The Post has learned. That leaves toymaker Basic Fun scrambling to find a new factory to manufacture the century-old brand that was founded by Frank Lloyd Wright’s son, John, and