Log Message:
pkgtools/mktool: update to 0.1.15

 - distinfo: Fix test_distinfo_just_distinfo.
 - distinfo: Use pkgsrc::distinfo::Distinfo.
 - distinfo: Test algorithm order.
 - distinfo: Add invalid file tests.
 - distinfo: Test file input modes.
 - checksum: Simplify previous test.
 - checksum: Test file input modes.
 - distinfo: Add initial integration tests.
 - checksum: cargo fmt.
 - checksum: Use format!() for clarity.
 - checksum: Fix error messages.
 - checksum: Split tests into separate functions.
 - checksum: Include invalid file in previous.
 - checksum: Test output order.