import: report directory-relative paths in error messages (issue5224) Import uses paths relative to the root of the repository, so when user imports patch with paths relative to the current working directory import aborts with 'unable to find file for patching'. This patch improves this situation by warning the user that paths are relative to the root of repository when patching fails.

#require docutils gettext

  $ $TESTDIR/check-gendoc el
  checking for parse errors