extdiff: preserve execute-bit across copies (
issue1562)
Bug report and test by Mads Kiilerich <mads@kiilerich.com>
# should print nothing
# should fail
abort: path 'b/x' is inside repo 'b'
abort: path 'b/x' is inside repo 'b'
# should fail
abort: path 'b/x' is inside repo 'b'
# should arguably print nothing
# should fail
abort: path 'b/a' is inside repo 'b'