Resolve libs for executable links in COPY_AS_IS

Do not skip symbolic links when adding libraries required by executables
in COPY_AS_IS. The symlink targets will be copied later by
build/default/490_fix_broken_links.sh.  We thus need library
dependencies for symlinked executables just like for normal executables
and build/default/490_fix_broken_links.sh does not perform library
dependency scan, so we need to do it at the same place as for normal
executables (in build/GNU/Linux/100_copy_as_is.sh). Otherwise it can
happen that we add a (broken) symlink via COPY_AS_IS, the actual
executable is then added by build/default/490_fix_broken_links.sh, but
without its libraries, and "rear mkrescue" then fails because required
libraries are missing. Happens for example with
/usr/lib/systemd/systemd-sysv-install, which is a symlink to
/bin/chkconfig and gets added to COPY_AS_IS in
prep/GNU/Linux/280_include_systemd.sh.

Gets rid of one exception for symlinks, which looks good in any case
(shorter and simpler code).

usr/share/rear/build/GNU/Linux/100_copy_as_is.sh

@@ -135,10 +135,11 @@ local copy_as_is_file=""
 # cf. https://github.com/rear/rear/pull/2378
 # It is crucial to append to /dev/$DISPENSABLE_OUTPUT_DEV (cf. 'Print' in lib/_input-output-functions.sh):
 while read -r copy_as_is_file ; do
-    # Skip non-regular files like directories, device files, and 'tar' error messages (e.g. in case of non-existent files, see above):
+    # Skip non-regular files like directories, device files, and 'tar' error messages (e.g. in case of non-existent files, see above)
+    # but do not skip symbolic links. Their targets will be copied later by build/default/490_fix_broken_links.sh.
+    # We thus need library dependencies for symlinked executables just like for normal executables
+    # and build/default/490_fix_broken_links.sh does not perform library dependency scan.
     test -f "$copy_as_is_file" || continue
-    # Skip symbolic links (only care about symbolic link targets):
-    test -L "$copy_as_is_file" && continue
     # Remember actual regular files that are executable:
     test -x "$copy_as_is_file" && copy_as_is_executables+=( "$copy_as_is_file" )
 done < <( sort -u $copy_as_is_filelist_file ) 2>>/dev/$DISPENSABLE_OUTPUT_DEV