gnulib-tool.py: Follow gnulib-tool changes, part 20. Follow gnulib-tool changes 2016-01-15 Paul Eggert <eggert@cs.ucla.edu> gnulib-tool: don't assume ln -s works 2016-01-24 Paul Eggert <eggert@cs.ucla.edu> gnulib-tool: don't give up on ln -s so easily 2017-06-08 Bruno Haible <bruno@clisp.org> gnulib-tool: Fix bug in func_ln_s, from 2016-01-15. * pygnulib/constants.py (symlink_relative): New function. (link_relative): Use it instead of os.symlink.