Thanks, these were bugs in the test cases. They were fixed here:
http://git.savannah.gnu.org/cgit/gzip.git/commit/?id=a963e3a42d6da62ef6d017f28ded08534ad4c805 and here: http://git.savannah.gnu.org/cgit/gzip.git/commit/?id=6263972df3140affd285399b7957de0a17370577 The fixes should appear in the next gzip version, so I'm closing the bug report.
