MFC r320210:

join(1): Fix field ordering for -v output

Per POSIX, join(1) (in modes other than -o) is a concatenation of selected
character fields.  The joined field is first, followed by fields in the
order they occurred in the input files.

Our join(1) utility previously handled this correctly for lines with a match
in the other file.  But it failed to order output fields correctly for
unmatched lines, printed in -a and -v modes.

A simple test case is:

$ touch a
$ echo "2 1" > b
$ join -v2 -2 2 a b
1 2

PR:		217711

1 files changed, 8 insertions, 2 deletions

diff --git a/usr.bin/join/join.c b/usr.bin/join/join.c
index 74f7dc7..63dccb7 100644
--- a/usr.bin/join/join.c
+++ b/usr.bin/join/join.c
@@ -469,9 +469,15 @@ outoneline(INPUT *F, LINE *lp)
 			else
 				outfield(lp, 0, 1);
 		}
-	else
+	else {
+		/*
+		 * Output the join field, then the remaining fields.
+		 */
+		outfield(lp, F->joinf, 0);
 		for (cnt = 0; cnt < lp->fieldcnt; ++cnt)
-			outfield(lp, cnt, 0);
+			if (F->joinf != cnt)
+				outfield(lp, cnt, 0);
+	}
 	(void)printf("\n");
 	if (ferror(stdout))
 		err(1, "stdout");