No changes in Swift or SwiftPM at the time, but I am seeing:
/Users/buildnode/jenkins/workspace/oss-swift-4.2-package-osx/swiftpm/Tests/FunctionalTests/MiscellaneousTests.swift:215: error: -[FunctionalTests.MiscellaneousTestCase testSecondBuildIsNullInModulemapGen] : XCTAssertTrue failed - 14:13:12 Test Case '-[FunctionalTests.MiscellaneousTestCase testSecondBuildIsNullInModulemapGen]' failed (2.321 seconds).