feat(checkpkg): enhance diff command for comparing file lists

Replace `sdiff` with `diff` (also from `diffutils`) with the following
parameters:

- `--side-by-side` for the `sdiff`-like output
- `--suppress-common-lines` for the `sdiff -s` behavior
- `--width="$COLUMNS"` to use the full terminal width (long lines are
  still truncated but it is definitely better than the default width of
  130 chars)
- `--color=auto` just because 😉

1 files changed, 1 insertions, 1 deletions

diff --git a/src/checkpkg.in b/src/checkpkg.in
index ccb7259..6ee18c6 100644
--- a/src/checkpkg.in
+++ b/src/checkpkg.in
@@ -140,7 +140,7 @@ for _pkgname in "${pkgname[@]}"; do
 	bsdtar tf "$TEMPDIR/$oldpkg" | sort > "$TEMPDIR/filelist-$_pkgname-old"
 	bsdtar tf "$pkgfile" | sort > "$TEMPDIR/filelist-$_pkgname"
 
-	sdiff -s "$TEMPDIR/filelist-$_pkgname-old" "$TEMPDIR/filelist-$_pkgname"
+	diff --side-by-side --suppress-common-lines --width="$COLUMNS" --color=auto "$TEMPDIR/filelist-$_pkgname-old" "$TEMPDIR/filelist-$_pkgname"
 
 	find-libprovides "$TEMPDIR/$oldpkg" 2>/dev/null | sort > "$TEMPDIR/libraries-$_pkgname-old"
 	find-libprovides "$pkgfile" 2>/dev/null | sort > "$TEMPDIR/libraries-$_pkgname"