[bugfix][DuneSymlinOrCopy] throw an error when symlink is called and

source and binary dir are the same. This will lead to files being
replaced by empty links.
7 jobs for bugfix/dune-symlink-or-copy in 10 minutes and 21 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #67448
duneci
debian:10 clang-6-libcpp-17

00:08:34

passed #67446
duneci iset:avx allowed to fail
debian:10 gcc-7-14--expensive

00:06:31

passed #67447
duneci
debian:10 gcc-8-noassert-17

00:10:21

passed #67450
duneci
debian:9 clang-3.8-14

00:01:48

passed #67449
duneci
debian:9 gcc-6-14

00:06:13

passed #67451
duneci
ubuntu:16.04 gcc-5-14

00:05:34

passed #67452
duneci
ubuntu:18.04 clang-6-17

00:02:27